Lexeme

A lexeme is the smallest or minimal unit of lexicon in a language that bears some “meaning”

In a text line, each word can be considered as a lexeme, and the spaces separating the words from each other can be considered as delimiters.

Sources:

Geert E. Booij, ‎Christian Lehmann Morphologie / Morphology. 1. Halbband – 2008 – 1000p. – 596