一定

一定	yī dìng	surely / certainly / necessarily / fixed / a certain (extent etc) / given / particular / must
一	yī	one / single / a (article) / as soon as / entire; whole; all; throughout / "one" radical in Chinese characters (Kangxi radical 1) / also pr. [yao1] for greater clarity when spelling out numbers digit by digit
定	dìng	to fix; to set; to make definite / to subscribe to (a newspaper etc); to book (tickets etc); to order (goods etc) / to congeal; to coagulate / (literary) definitely