: any of an order (Hemiptera and especially its suborder Heteroptera) of insects (such as an assassin bug or chinch bug) that have sucking mouthparts, forewings thickened at the base, and incomplete metamorphosis and are often economic pests
called alsotrue bug
b
: any of various small arthropods (such as a beetle or spider) resembling the true bugs
c
: any of several insects (such as a head louse) commonly considered obnoxious
2
: an unexpected defect, fault, flaw, or imperfection
the software was full of bugs
3
a
: a microorganism (such as a bacterium or virus) especially when causing illness or disease
b
: an often unspecified or nonspecific sickness presumed to be caused by such a microorganism