canary

Etymology

From French canarie, from Spanish canario, from the Latin Canariae insulae (“Canary Islands”) (Spanish Islas Canarias); from the largest island Insula Canaria (“Dog Island" or "Canine Island”), named for its dogs, from canārius (“canine”), from canis (“dog”).

noun

1. A small, usually yellow, finch (genus Serinus), a songbird native to the Canary Islands.
2. Any of various small birds of different countries, most of which are largely yellow in colour.
3. (informal) A female singer, soprano, a coloratura singer.
4. (slang) An informer or snitch; a squealer.
5. A light, slightly greenish, yellow colour.
   canary:
6. (slang) A (usually yellow) capsule of the short-acting barbiturate pentobarbital/pentobarbitone (Nembutal).
7. (Australia, informal) A yellow sticker applied by the police to a vehicle to indicate it is unroadworthy.
   The tendency in these types of situations (as far as I can see) is that because I don't think the act itself is illegal, the police will go through your vehicle systematically loking for anything wrong with it, to slap a canary on it (that's slang for an unroadworthy sticker) or present you with some other fine. September 12, 1993, Jacco Zwetsloot, “Warning About Speed Traps”, in alt.folklore.urban (Usenet)
   Yes, if the exhaust is to noisey they can slap a yellow canary on it, but the[n] who cares you got rid of it. January 16, 1999, Garry Lawson, “Noisy Bikes (Update)”, in aus.motorcycles (Usenet)
   You don't have to carry a spare wheel for a car to be roadworthy, and if you *do* carry one, it doesn't have to be in a roadworthy condition *unless* you fit it [to] the car and drive on it. / If it's not and you get pinched, expect a canary... February 14, 2003, Noddy, “Spare tyres”, in aus.cars (Usenet)
8. Any test subject, especially an inadvertent or unwilling one. (From the mining practice of using canaries to detect dangerous gases.)
9. (computing) A value placed in memory such that it will be the first data corrupted by a buffer overflow, allowing the program to identify and recover from it.
10. (computing) A change that is tested by being rolled out first to a subset of machines or users before rolling out to all.
11. (countable, uncountable) A light, sweet, white wine from the Canary Islands.
12. A lively dance, possibly of Spanish origin (also called canaries).

adj

1. Of a light yellow colour.

verb

1. (intransitive) to dance nimbly (as in the canary dance)
2. (slang) to inform or snitch, to betray secrets, especially about illegal activities.
3. (computing) to test a software change by rolling out to a small set of machines or users before making it available to all.