Bug \Bug\, n. [OE. bugge, fr. W. bwg, bwgan, hobgoblin, scarecrow, bugbear. Cf. Bogey, Boggle.]

1. A bugbear; anything which terrifies. [Obs.]

Sir, spare your threats: The bug which you would fright me with I seek. --Shak.

2. (Zo["o]l.) A general name applied to various insects belonging to the Hemiptera; as, the squash bug; the chinch bug, etc.

3. (Zo["o]l.) An insect of the genus Cimex, especially the bedbug (C. lectularius). See Bedbug.

4. (Zo["o]l.) One of various species of Coleoptera; as, the ladybug; potato bug, etc.; loosely, any beetle.

5. (Zo["o]l.) One of certain kinds of Crustacea; as, the sow bug; pill bug; bait bug; salve bug, etc.

Note: According to present popular usage in England, and among housekeepers in America, bug, when not joined with some qualifying word, is used specifically for bedbug. As a general term it is used very loosely in America, and was formerly used still more loosely in England. ``God's rare workmanship in the ant, the poorest bug that creeps.'' --Rogers (--Naaman). ``This bug with gilded wings.'' --Pope.

Bait bug. See under Bait.

Bug word, swaggering or threatening language. [Obs.]

--Beau. & Fl.

Source: Webster's Revised Unabridged Dictionary (1913)