ILLNESS › a bacteria or virus, or the illness that it causes: a flu / stomach bug
COMPUTER › a mistake in a computer program: This program is full of bugs.
INSECT › a small insect
EQUIPMENT › a small, electronic piece of equipment used to secretly listen to people talking
be bitten by the bug/get the bug informal › to develop a strong interest or enthusiasm for a particular activity: He's been bitten by the tennis bug.