n. 25B6; noun this fact is the bedrock of our authority : CORE, basis, base, foundation, roots, heart, backbone, principle, essence, nitty-gritty; informal nuts and bolts.
BEDROCK
Meaning of BEDROCK in English
Concise Oxford thesaurus English vocabulary. Краткий оксфордский словарь английского языка тезаурус. 2012