Meaning of BASIS in English

[noun] [C] [plural] bases - the most important facts, ideas, etc. from which something is developedThis design was the basis for the large painting he did later.Their proposals have no proven scientific basis.Decisions were often made on the basis of (= using) incorrect information.A basis is also a way or method of doing something.Most of our staff work for us on a voluntary basis (= They work without being paid).

Cambridge English vocab.      Кембриджский английский словарь.