This chapter highlights the fundamental assumptions shared by all constructionist approaches, distinguishing them from mainstream generative grammar. In particular, phrasal constructions, like traditional lexical items, are learned pairings of form and function. Grammar does not involve any transformational or derivational component. Phrasal constructions, words, and partially filled words (aka morphemes) are related in a network in which nodes are related by inheritance links. Languages are acknowledged to vary in wide-ranging ways; the cross-linguistic generalizations that do exist are explained by domain-general cognitive processes or by the functions of the constructions involved.