Synonyms of foundations

1 Syllable
nub, guts, heart, abcs, stay, bed, base, root, prop, foot, ground
2 Syllables
support, bottom, basics, bedrock, groundwork, footing, reason
3 Syllables
substratum
4 Syllables
authority, nitty-gritty, substructure, underpinning
5 Syllables
infrastructure, justification, understructure