口こう針しんMeanings1nounstylet; mouth styletA biological term for a needle-like mouthpart found in certain invertebrates, such as nematodes and some insects, used for piercing and feeding.線せん虫ちゅうの口こう針しんは植しょく物ぶつの細さい胞ぼうに穴あなを開あけるために使つかわれる。The nematode's stylet is used to pierce plant cells.