rudiment

nouns

the elementary stages of any subject (usually plural)
"he mastered only the rudiments of geometry"
ABC, ABC's, ABCs, alphabet, first principle, first rudiment, rudiment
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"
rudiment
is derived from
rudimentary
is derived from
rudimentary
is a type of (narrower)
any part of an organism such as an organ or extremity
body part