bug   (bŭg)    n.   A true bug. An insect or similar organism, such as a centipede or an earwig. See Regional Note at lightning bug. A disease-producing microorganism: a flu bug. The illness or disease so produced: "stomach flu, a cold, or just some bug going around" (David Smollar). A defect or difficulty, as in a system or design. Computer Science A defect in the code or routine of a program. A defect or difficulty, as in a system or design. Computer Science A defect in the code or routine of a program. An enthusiasm or obsession: got bitten by the writing bug. An enthusiast or devotee; a buff: a model train bug. An electronic listening device, such as a hidden microphone or wiretap, used in surveillance: planted a bug in the suspect's room. v.   bugged, bug·ging, bugs v.   intr. To grow large; bulge: My eyes bugged when I saw the mess. v.   tr. To annoy; pester. To prey on; worry: a memory that bugged me for years. To equip (a room or telephone circuit, for example) with a concealed electronic listening device. To make (the eyes) bulge or grow large. To leave or quit, usually in a hurry. To avoid a responsibility or duty. Often used with on or of: bugged out on his partners at the first sign of trouble. Phrasal Verb(s): bug off Slang To leave someone alone; go away. bug out Slang To leave or quit, usually in a hurry. To avoid a responsibility or duty. Often used with on or of: bugged out on his partners at the first sign of trouble. Idiom(s): put a bug in (someone's) ear Informal To impart useful information to (another) in a subtle, discreet way. [Origin unknown.] bug'ger n.

Bug

Bug\, n. [OE. bugge, fr. W. bwg, bwgan, hobgoblin, scarecrow, bugbear. Cf. Bogey, Boggle.]

1. A bugbear; anything which terrifies. [Obs.]

Sir, spare your threats: The bug which you would fright me with I seek. --Shak.

2. (Zo["o]l.) A general name applied to various insects belonging to the Hemiptera; as, the squash bug; the chinch bug, etc.

3. (Zo["o]l.) An insect of the genus Cimex, especially the bedbug (C. lectularius). See Bedbug.

4. (Zo["o]l.) One of various species of Coleoptera; as, the ladybug; potato bug, etc.; loosely, any beetle.

5. (Zo["o]l.) One of certain kinds of Crustacea; as, the sow bug; pill bug; bait bug; salve bug, etc.

Note: According to present popular usage in England, and among housekeepers in America, bug, when not joined with some qualifying word, is used specifically for bedbug. As a general term it is used very loosely in America, and was formerly used still more loosely in England. "God's rare workmanship in the ant, the poorest bug that creeps." --Rogers (--Naaman). "This bug with gilded wings." --Pope.

Bait bug. See under Bait.

Bug word, swaggering or threatening language. [Obs.] --Beau. & Fl.

bug

A generic term that describes a malfunction of undetermined origin in a computer or other electronic device.

Note: The term originated in the 1940s when the examination of a large computer revealed that an actual insect had landed on one of the circuits, shorting it out and shutting the machine down.

bug

n. An unwanted and unintended property of a program or piece of hardware, esp. one that causes it to malfunction. Antonym of feature. Examples: "There's a bug in the editor: it writes things out backwards." "The system crashed because of a hardware bug." "Fred is a winner, but he has a few bugs" (i.e., Fred is a good guy, but he has a few personality problems).

Historical note: Admiral Grace Hopper (an early computing pioneer better known for inventing COBOL) liked to tell a story in which a technician solved a glitch in the Harvard Mark II machine by pulling an actual insect out from between the contacts of one of its relays, and she subsequently promulgated bug in its hackish sense as a joke about the incident (though, as she was careful to admit, she was not there when it happened). For many years the logbook associated with the incident and the actual bug in question (a moth) sat in a display case at the Naval Surface Warfare Center (NSWC). The entire story, with a picture of the logbook and the moth taped into it, is recorded in the "Annals of the History of Computing", Vol. 3, No. 3 (July 1981), pp. 285-286.

The text of the log entry (from September 9, 1947), reads "1545 Relay #70 Panel F (moth) in relay. First actual case of bug being found". This wording establishes that the term was already in use at the time in its current specific sense -- and Hopper herself reports that the term `bug' was regularly applied to problems in radar electronics during WWII.

Indeed, the use of `bug' to mean an industrial defect was already established in Thomas Edison's time, and a more specific and rather modern use can be found in an electrical handbook from 1896 ("Hawkin's New Catechism of Electricity", Theo. Audel & Co.) which says: "The term `bug' is used to a limited extent to designate any fault or trouble in the connections or working of electric apparatus." It further notes that the term is "said to have originated in quadruplex telegraphy and have been transferred to all electric apparatus."

The latter observation may explain a common folk etymology of the term; that it came from telephone company usage, in which "bugs in a telephone cable" were blamed for noisy lines. Though this derivation seems to be mistaken, it may well be a distorted memory of a joke first current among _telegraph_ operators more than a century ago!

Or perhaps not a joke. Historians of the field inform us that the term "bug" was regularly used in the early days of telegraphy to refer to a variety of semi-automatic telegraphy keyers that would send a string of dots if you held them down. In fact, the Vibroplex keyers (which were among the most common of this type) even had a graphic of a beetle on them (and still do)! While the ability to send repeated dots automatically was very useful for professional morse code operators, these were also significantly trickier to use than the older manual keyers, and it could take some practice to ensure one didn't introduce extraneous dots into the code by holding the key down a fraction too long. In the hands of an inexperienced operator, a Vibroplex "bug" on the line could mean that a lot of garbled Morse would soon be coming your way.

Further, the term "bug" has long been used among radio technicians to describe a device that converts electromagnetic field variations into acoustic signals. It is used to trace radio interference and look for dangerous radio emissions. Radio community usage derives from the roach-like shape of the first versions used by 19th century physicists. The first versions consisted of a coil of wire (roach body), with the two wire ends sticking out and bent back to nearly touch forming a spark gap (roach antennae). The bug is to the radio technician what the stethoscope is to the stereotype medical doctor. This sense is almost certainly ancestral to modern use of "bug" for a covert monitoring device, but may also have contributed to the use of "bug" for the effects of radio interference itself.

Actually, use of `bug' in the general sense of a disruptive event goes back to Shakespeare! (Henry VI, part III - Act V, Scene II: King Edward: "So, lie thou there. Die thou; and die our fear; For Warwick was a bug that fear'd us all.") In the first edition of Samuel Johnson's dictionary one meaning of `bug' is "A frightful object; a walking spectre"; this is traced to `bugbear', a Welsh term for a variety of mythological monster which (to complete the circle) has recently been reintroduced into the popular lexicon through fantasy role-playing games.

In any case, in jargon the word almost never refers to insects. Here is a plausible conversation that never actually happened:

"There is a bug in this ant farm!"

"What do you mean? I don't see any ants in it."

"That's the bug."

A careful discussion of the etymological issues can be found in a paper by Fred R. Shapiro, 1987, "Entomology of the Computer Bug: History and Folklore", American Speech 62(4):376-378.

[There has been a widespread myth that the original bug was moved to the Smithsonian, and an earlier version of this entry so asserted. A correspondent who thought to check discovered that the bug was not there. While investigating this in late 1990, your editor discovered that the NSWC still had the bug, but had unsuccessfully tried to get the Smithsonian to accept it -- and that the present curator of their History of American Technology Museum didn't know this and agreed that it would make a worthwhile exhibit. It was moved to the Smithsonian in mid-1991, but due to space and money constraints was not actually exhibited years afterwards. Thus, the process of investigating the original-computer-bug bug fixed it in an entirely unexpected way, by making the myth true! --ESR]

bug 

Main Entry: bug
Function: transitive verb
Inflected Forms: bugged; bug·ging
: to plant a concealed microphone in <bug an office> —compare EAVESDROP, WIRETAP

Main Entry: bug
Pronunciation: 'b&g
Function: noun
1 a : an insect or other creeping or crawling invertebrate animal (as a spider) —notused technically b : any of various insects commonly considered especially obnoxious: as (1) : BEDBUG(2) : COCKROACH (3) : HEAD LOUSE c : any of the order Hemiptera and especially of its suborder Heteroptera of insects that have sucking mouthparts, forewings thickened at the base, and that lack a pupal stage betweenthe immature stages and the adult called also true bug
2 a : a disease-producing microorganism and especially a germ b : a disease caused by suchmicroorganisms; especially : any of various respiratory conditions (as influenza or grippe) of virus origin

bug (bŭg)
n.

1. A true bug, specifically one having a beaklike structure that allows piercing and sucking.
2. An insect or similar organism, such as a centipede or an earwig.
3. A disease-producing microorganism, such as a flu bug.
4. The illness or disease so produced.
5. A defect or difficulty, as in a system or design.

bug   (bŭg)  Pronunciation Key  An insect belonging to the suborder Heteroptera. See more at true bug. An insect, spider, or similar organism. Not in scientific use. Our Living Language  : The word bug is often used to refer to tiny creatures that crawl along, such as insects and even small animals that are not insects, such as spiders and millipedes. But for scientists the word has a much narrower meaning. In the strictest terms bugs are those insects that have mouthparts adapted for piercing and sucking. The mouthparts of these bugs are contained in a beak-shaped structure. Thus scientists would classify a louse but not a beetle or a cockroach as a bug. In fact, scientists often call lice and their relatives true bugs to distinguish them better from what everyone else calls "bugs."

bug programming
An unwanted and unintended property of a program or piece of hardware, especially one that causes it to malfunction. Antonym of feature. E.g. "There's a bug in the editor: it writes things out backward." The identification and removal of bugs in a program is called "debugging".
Admiral Grace Hopper (an early computing pioneer better known for inventing COBOL) liked to tell a story in which a technician solved a glitch in the Harvard Mark II machine by pulling an actual insect out from between the contacts of one of its relays, and she subsequently promulgated bug in its hackish sense as a joke about the incident (though, as she was careful to admit, she was not there when it happened). For many years the logbook associated with the incident and the actual bug in question (a moth) sat in a display case at the Naval Surface Warfare Center (NSWC). The entire story, with a picture of the logbook and the moth taped into it, is recorded in the "Annals of the History of Computing", Vol. 3, No. 3 (July 1981), pp. 285--286.
The text of the log entry (from September 9, 1947), reads "1545 Relay #70 Panel F (moth) in relay. First actual case of bug being found". This wording establishes that the term was already in use at the time in its current specific sense - and Hopper herself reports that the term "bug" was regularly applied to problems in radar electronics during WWII.
Indeed, the use of "bug" to mean an industrial defect was already established in Thomas Edison's time, and a more specific and rather modern use can be found in an electrical handbook from 1896 ("Hawkin's New Catechism of Electricity", Theo. Audel & Co.) which says: "The term "bug" is used to a limited extent to designate any fault or trouble in the connections or working of electric apparatus." It further notes that the term is "said to have originated in quadruplex telegraphy and have been transferred to all electric apparatus."
The latter observation may explain a common folk etymology of the term; that it came from telephone company usage, in which "bugs in a telephone cable" were blamed for noisy lines. Though this derivation seems to be mistaken, it may well be a distorted memory of a joke first current among *telegraph* operators more than a century ago!
Actually, use of "bug" in the general sense of a disruptive event goes back to Shakespeare! In the first edition of Samuel Johnson's dictionary one meaning of "bug" is "A frightful object; a walking spectre"; this is traced to "bugbear", a Welsh term for a variety of mythological monster which (to complete the circle) has recently been reintroduced into the popular lexicon through fantasy role-playing games.
In any case, in jargon the word almost never refers to insects. Here is a plausible conversation that never actually happened:
"There is a bug in this ant farm!"
"What do you mean? I don't see any ants in it."
"That's the bug."
[There has been a widespread myth that the original bug was moved to the Smithsonian, and an earlier version of this entry so asserted. A correspondent who thought to check discovered that the bug was not there. While investigating this in late 1990, your editor discovered that the NSWC still had the bug, but had unsuccessfully tried to get the Smithsonian to accept it - and that the present curator of their History of American Technology Museum didn't know this and agreed that it would make a worthwhile exhibit. It was moved to the Smithsonian in mid-1991, but due to space and money constraints has not yet been exhibited. Thus, the process of investigating the original-computer-bug bug fixed it in an entirely unexpected way, by making the myth true! - ESR]
[The Jargon File]
(1999-06-29)

bug

In addition to the idioms beginning with bug, also see cute as a button (bug's ear); put a bug in someone's ear; snug as a bug in a rug; what's eating (bugging) you.