- rudiment, first rudiment, first principle, alphabet, ABC, ABC's, ABCs - the elementary stages of any subject (usually plural); "he mastered only the rudiments of geometry"
--1 is a kind of fundamentals, basics, fundamental principle, basic principle, bedrock; fundamentals, basics, fundamental principle, basic principle, bedrock; fundamentals, basics, fundamental principle, basic principle, bedrock; fundamentals, basics, fundamental principle, basic principle, bedrock