- base, basisThe two words overlap in meaning, but broadly base is physical (the base of a column, a poison with an arsenic base), while basis is figurative with a primary meaning ‘that on which something depends’, as in a basis for action, the basis of an argument, or doing things on a friendly basis. Expressions such as on a regular basis, on a daily basis, and on a voluntary basis are sometimes frowned on when simpler adverbs (regularly, daily, voluntarily) are available, but the longer forms often make the point more effectively, can produce a better sentence balance, and are well established. Base is occasionally found in figurative meanings too, especially in semi-fixed collocations such as customer (or client) base and base of support. In language, it has the special meaning of a philological root (The word cairn is derived from a Celtic base).
Modern English usage. 2014.