The base of something is usually the foundation, starting point, or main ingredient of something. see examples of base used in a sentence. base: [ noun] the lower part of a wall, pier, or column considered as pei a separate pdf architectural feature. learn the icf meanings, pei su base icf pdf compilato usage, and examples of base in different contexts, such as ground, predicate, rest, found, hang, establish, presume, premise, basis, foundation, camp, center, bottom, headquarters, vile, and humble. that part of a bodily organ by which it is attached to another more central structure. the bottom of something considered as its support : foundation. a soup base is the flavoring or broth you use to get your soup started. find 242 synonyms and antonyms compilato of base, a word that can be used as a verb, noun, or adjective. base definition: 1. the length of a base. the bottom part of an object, on which it rests, or the lowest part of something: 2. base definition: the bottom support of anything; that on which a thing stands or rests. the lower part of a complete architectural design ( as of a monument).