rudiment
n.
1540s, from Middle French rudiment (16c.) or directly from Latin rudimentum "early training, first experience, beginning, first principle," from rudis "unlearned, untrained" (see rude). Related: Rudiments.
〔蒋〕[rud原始→开始，起初，初步，-i-，-ment名词后缀] 初步，入门，基础，基本原理