Easton's Bible Dictionary
Birds are divided in the Mosaic law into two classes, (1) the clean (Leviticus 1:14-17; 5:7-10; 14:4-7), which were offered in sacrifice; and (2) the unclean (Leviticus 11:13-20). When offered in sacrifice, they were not divided as other victims were (Genesis 15:10). They are mentioned also as an article of food (Deuteronomy 14:11). The art of snaring wild birds is referred to (Psalm 124:7; Proverbs 1:17; 7:23; Jeremiah 5:27). Singing birds are mentioned in Psalm 104:12; Ecclesiastes 12:4. Their timidity is alluded to (Hosea 11:11). The reference in Psalm 84:3 to the swallow and the sparrow may be only a comparison equivalent to, "What her house is to the sparrow, and her nest to the swallow, that thine altars are to my soul."
Noah Webster's New International Dictionary of the English Language
1. (n.) Orig., a chicken; the young of a fowl; a young eaglet; a nestling; and hence, a feathered flying animal (see 2).
2. (n.) A warm-blooded, feathered vertebrate provided with wings. See Aves.
3. (n.) Specifically, among sportsmen, a game bird.
4. (n.) Fig.: A girl; a maiden.
5. (v. i.) To catch or shoot birds.
6. (v. i.) Hence: To seek for game or plunder; to thieve.