This paper presents the hypothesis that words (and not morphemes) are the minimal units of connection between sound and meaning in human languages. Such a proposal implies the definition of the word as a categorized syntactic derivation that is linked in memory to a representation in the sensorimotor system. The main implications of the hypothesis are the following: (i) A non-lexicalist model is compatible with the phenomena of lexical integrity and lack of productivity that motivate lexicalist models. (ii) It can be concluded that bound morphemes (roots and affixes) are neither syntactic nor conceptual entities, but purely morpho-phonological ones. Morphemes are side effects of linguistic change operating as resources to optimize the processing and memorization of words. And (iii) a neo-constructionist conception of words is made compatible with a paradigmatic morphology.