The Collaborative International Dictionary of English v.0.48:
Deer \Deer\ (d[=e]r), n. sing. & pl. [OE. der, deor, animal,
wild animal, AS. de['o]r; akin to D. dier, OFries. diar, G.
thier, tier, Icel. d[=y]r, Dan. dyr, Sw. djur, Goth. dius; of
unknown origin. [root]71.]
1. Any animal; especially, a wild animal. [Obs.] --Chaucer.
Mice and rats, and such small deer. --Shak.
The camel, that great deer. --Lindisfarne
2. (Zool.) A ruminant of the genus Cervus, of many species,
and of related genera of the family Cervid[ae]. The
males, and in some species the females, have solid
antlers, often much branched, which are shed annually.
Their flesh, for which they are hunted, is called
Note: The deer hunted in England is Cervus elaphus, called
also stag or red deer; the fallow deer is Cervus
dama; the common American deer is Cervus
Virginianus; the blacktailed deer of Western North
America is Cervus Columbianus; and the mule deer of
the same region is Cervus macrotis. See Axis,
Fallow deer, Mule deer, Reindeer.
Note: Deer is much used adjectively, or as the first part of
a compound; as, deerkiller, deerslayer, deerslaying,
deer hunting, deer stealing, deerlike, etc.
Deer mouse (Zool.), the white-footed mouse (Peromyscus
leucopus, formerly Hesperomys leucopus) of America.
Small deer, petty game, not worth pursuing; -- used
metaphorically. (See citation from Shakespeare under the
first definition, above.) "Minor critics . . . can find
leisure for the chase of such small deer." --G. P. Marsh.