1 [lawg, log]
a portion or length of the trunk or of a large limb of a felled tree.
something inert, heavy, or not sentient.
Nautical. any of various devices for determining the speed of a ship, as a chip log or patent log.
any of various records, made in rough or finished form, concerning a trip made by a ship or aircraft and dealing with particulars of navigation, weather, engine performance, discipline, and other pertinent details; logbook.
Movies. an account describing or denoting each shot as it is taken, written down during production and referred to in editing the film.
a register of the operation of a machine.
Also called well log. a record kept during the drilling of a well, especially of the geological formations penetrated.
Computers. any of various chronological records made concerning the use of a computer system, the changes made to data, etc.
Radio and Television. a written account of everything transmitted by a station or network.
Also called log of wood. Australian Slang. a lazy, dull-witted person; fool.
verb (used with object), logged, logging.
to cut (trees) into logs: to log pine trees for fuel.
to cut down the trees or timber on (land): We logged the entire area in a week.
to enter in a log; compile; amass; keep a record of: to log a day's events.
to make (a certain speed), as a ship or airplane: We are logging 18 knots.
to travel for (a certain distance or a certain amount of time), according to the record of a log: We logged 30 miles the first day. He has logged 10,000 hours flying time.
verb (used without object), logged, logging.
to cut down trees and get out logs from the forest for timber: to log for a living.
Verb phrases
log in,
Also, log on, sign on. Computers. to enter identifying data, as a username or password, into a database, mobile device, or computer, especially a multiuser computer or a remote or networked system, so as to to access and use it: Log in to start your work session. Log in to your account to pay your bill online.
to enter or include any item of information or data in a record, account, etc.
log off/out, Computers. to terminate a session.

1350–1400; Middle English logge, variant of lugge pole, limb of tree; compare obsolete logget pole; see lugsail, logbook

loggish, adjective
unlogged, adjective
Dictionary.com Unabridged


2 [lawg, log]
Mathematics, logarithm.


variant of logo- before a vowel: logarithm.


variant of -logue: analog.


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Based on the Random House Dictionary, © Random House, Inc. 2014.
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World English Dictionary
log1 (lɒɡ)
1.  a.  a section of the trunk or a main branch of a tree, when stripped of branches
 b.  (modifier) constructed out of logs: a log cabin
2.  a.  a detailed record of a voyage of a ship or aircraft
 b.  a record of the hours flown by pilots and aircrews
 c.  a book in which these records are made; logbook
3.  a written record of information about transmissions kept by radio stations, amateur radio operators, etc
4.  a.  See also chip log a device consisting of a float with an attached line, formerly used to measure the speed of a ship
 b.  heave the log to determine a ship's speed with such a device
5.  (Austral) a claim for better pay and conditions presented by a trade union to an employer
6.  like a log without stirring or being disturbed (in the phrase sleep like a log)
vb , logs, logging, logged
7.  (tr) to fell the trees of (a forest, area, etc) for timber
8.  (tr) to saw logs from (trees)
9.  (intr) to work at the felling of timber
10.  (tr) to enter (a distance, event, etc) in a logbook or log
11.  (tr) to record the punishment received by (a sailor) in a logbook
12.  (tr) to travel (a specified distance or time) or move at (a specified speed)
[C14: origin obscure]

log2 (lɒɡ)
short for logarithm

combining form
a US variant of -logue

Collins English Dictionary - Complete & Unabridged 10th Edition
2009 © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009
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Word Origin & History

late 14c., of unknown origin. O.N. had lag "felled tree" (from stem of liggja "to lie"), but on phonological grounds etymologists deny that this is the root of English log. Instead, they suggest an independent formation meant to "express the notion of something massive by a word of appropriate sound."
Logging "act of cutting timber" is from 1706. Logjam "congestion of logs on a river" is from 1885; in the figurative sense it is from 1890. Log cabin in Amer.Eng. has been a figure of the honest pioneer since the 1840 presidential campaign of William Henry Harrison.

"to enter into a log book," 1823, from logbook "daily record of a ship's speed, progress, etc." (1679), which is so called because wooden floats were used to measure a ship's speed. To log in in the computing sense is attested from 1963.
Online Etymology Dictionary, © 2010 Douglas Harper
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American Heritage
Science Dictionary
log   (lôg)  Pronunciation Key 
A logarithm.
The American Heritage® Science Dictionary
Copyright © 2002. Published by Houghton Mifflin. All rights reserved.
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Computing Dictionary

log definition

1. logarithm.
2. A record of the activity of some system, often stored in a particular file.
Different operating systems have different conventions and support for storing logs. Unix has the syslog system and the /var/log directory hierarchy, Microsoft Windows has event logs. Web servers, for example, typically record information about every page accessed in one or more "web logs".
The Free On-line Dictionary of Computing, © Denis Howe 2010 http://foldoc.org
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American Heritage
Abbreviations & Acronyms
The American Heritage® Abbreviations Dictionary, Third Edition
Copyright © 2005 by Houghton Mifflin Company.
Published by Houghton Mifflin Company. All rights reserved.
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Bible Dictionary

Log definition

the smallest measure for liquids used by the Hebrews (Lev. 14:10, 12, 15, 21, 24), called in the Vulgate sextarius. It is the Hebrew unit of measure of capacity, and is equal to the contents of six ordinary hen's eggs=the twelfth part of a him, or nearly a pint.

Easton's 1897 Bible Dictionary
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American Heritage
Idioms & Phrases


In addition to the idiom beginning with log, also see easy as pie (rolling off a log); like a bump on a log; sleep like a log.

The American Heritage® Dictionary of Idioms by Christine Ammer.
Copyright © 1997. Published by Houghton Mifflin.
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Example sentences
They may inhabit a tree hole, fallen log, or a house's attic.
It's not that the log house and studio aren't handsome.
And it contains a log of some of your private phone calls.
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