1 a very small piece; a bit 微粒；一点儿: dust particles 尘埃 ☞Look at alpha particle. 参看alpha particle。

2 (grammar语法) a small word that is not as important as a noun, verb or adjective 小品词（如介词、副词等）；介副词: In the phrasal verb ‘break down’, ‘down’ is an adverbial particle. 在短语动词break down中，down是副词小品词。