1 an illness that is caused by a bacterium or virus, or the bacterium or virus that causes it -- 感染症, (感染症を引き起こす)バクテリア、ウィルス
a stomach bug
2 a mistake in a computer program -- (コンピュータプログラムの)バグ, 不具合, 欠陥
3 a very small device, fixed on to a phone or hidden in a room, that allows you to listen to what people are saying without them knowing -- 盗聴器
4 to put special equipment somewhere in order to listen secretly to people’s conversations -- ~に盗聴器をしかける, ~を盗聴する