nitrous oxide (also laughing-gas)

gas sometimes used as an anaesthetic, esp by dentists 氧化亚氮, 笑气（有时用作麻醉剂, 尤用於牙科）.

ninny, ninth, ninthly, nip, nipper, nipple, nippy, nirvana, Nissen hut, nit, nit-picking, nitpick, nitpicking, nitrate, nitre (US niter), nitric, nitric acid, nitrogen, nitrogenous, nitrous, nitty-gritty, nitwit, nitwitted, nix, no, no doubt, no fewer than, no later than, no less, no less than, no longer, no man's land, no matter, no matter how, no more, no more than, no more(...)than, no more...than, no more...than..., no neg,