Synonyms:
basis, base, foundation, fundament, groundwork, cornerstone
Meaning: the fundamental assumptions from which something is begun or developed or calculated or explained; "the whole argument rested on a basis of conjecture"
Usage examples
With colours more, groundwork or broidery Never in cloth did Tartars make nor Turks, Nor were such tissues by Arachne laid.
Nevertheless, one must have a good groundwork of knowledge of books in order to avoid mistakes such as poor Irene made in talking with young Corey.