[thuhm] 
,| 1. | the short, thick, inner digit of the human hand, next to the forefinger. |
| 2. | the corresponding digit in other animals; pollex. |
| 3. | the part of a glove or mitten for containing this digit. |
| 4. | Architecture. an ovolo or echinus molding. |
| 5. | to soil or wear with the thumbs in handling, as the pages of a book. |
| 6. | to glance through (the pages of a book, leaflet, etc.) quickly. |
| 7. | to play (a guitar or other instrument) with or as with the thumbs. |
| 8. | (of a hitchhiker) to solicit or get (a ride) by pointing the thumb in the desired direction of travel. |
| 9. | all thumbs, awkward; clumsy; bungling: The visitor almost knocked over a vase and seemed to be all thumbs. |
| 10. | thumb one's nose,
|
| 11. | thumbs down, a gesture or expression of dissent or disapproval: We turned thumbs down to that suggestion. |
| 12. | thumbs up, a gesture or expression of assent or approval. |
| 13. | under one's thumb, under the power or influence of; subordinate to. Also, under the thumb of. |
| thumb (thŭm) n.
v. tr.
[Middle English, from Old English thūma; see teuə- in Indo-European roots.] |
thumb (thŭm)
n.
The short thick digit of the human hand, next to the index finger and opposable to each of the other four digits.
Thumb processor
An extension to the Advanced RISC Machine architecture, announced on 06 March 1995 by Advanced RISC Machines Ltd. By identifying the critical subset of the ARM instruction set and encoding it into 16 bits, ARM has succeeded in reducing typical program size by 30-40% from ARM's already excellent code density. Since this Thumb instruction set uses less memory for program storage, cost is further reduced.
All Thumb-aware processor cores combine the capability to execute both the 32-bit ARM and the 16-bit Thumb instruction sets. Careful design of the Thumb instructions allow them to be decompressed into full ARM instructions transparently during normal instruction decoding without any performance penalty. This differs from other 32-bit processors, like the Intel 486SX, with a 16-bit data bus, which require two 16-bit memory accesses to execute every 32-bit instruction and so halve performance.
The patented Thumb decompressor has been carefully designed with only a small amount of circuitry additional to the existing instruction decoder, so chip size and thus cost do not significantly increase. Designers can easily interleave fast ARM instructions (for performance critical parts of a program) with compact Thumb code to save memory.
(1995-03-14)
thumb jargon
The slider or "bubble" on a window system scrollbar. So called because moving it allows you to browse through the contents of a text window in a way analogous to thumbing through a book.
[The Jargon File]
(1995-03-14)
thumb
In addition to the idioms beginning with thumb, also see all thumbs; green thumb; rule of thumb; stick out (like a sore thumb); twiddle one's thumbs; under someone's thumb.
thumb
short, thick first digit of the human hand and of the lower-primate hand and foot. It differs from other digits in having only two phalanges (tubular bones of the fingers and toes). The thumb also differs in having much freedom of movement and being opposable to tips of other digits. The corresponding first digit (most medial digit) in other vertebrates is also called the thumb, especially if it has some manipulative or special ability (e.g., in the raccoon and the bat)
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