rudiment

英 ['ruːdɪm(ə)nt] 美['rʊdəmənt]

• n. 雏形；基本原理

1. the elementary stages of any subject (usually plural);

"he mastered only the rudiments of geometry"

2. the remains of a body part that was functional at an earlier stage of life;

"Meckel's diverticulum is the rudiment of the embryonic yolk sac"