keystone

n 1 (architecture 建) central stone at the top of an arch locking the others into position 拱顶石. 2 (usu sing 通常作单数) (fig 比喻) most important part of a plan, an argument, etc on which all the other parts depend （计划、 论据等的）基础, 主旨: Belief in a life after death is the keystone of her religious faith. 她的宗教信仰的基础是相信死後有来生. Cf 参看 corner-stone (corner1).

kerbstone, kerchief, kerfuffle, kernel, kerosene, kerosene, kerosine (also kerosine), kestrel, ketch, ketchup, kettle, kettledrum, key, key (also cay), key money, key signature, key-pad, key-ring, keyboard, keyhole, keynote, KG, KGB, khaki, kHz, kibbutz, kibbutznik, kick, kick-off, kick-start, kickback, kicker, kid, kid-glove, kid...into doing, kiddy (also kiddie), kidnap, kidnaper, kidnapper, kidnapping, kidney,