lexicalize

from The American Heritage® Dictionary of the English Language, 5th Edition.

• transitive verb To express using a word or words.
• transitive verb To incorporate into a language as a new word.
• transitive verb To treat (a phrase, expression, or other group of morphemes) as a single word.

from the GNU version of the Collaborative International Dictionary of English.

• transitive verb To make into a word, coin into a word.
• transitive verb To increase the importance of, or emphasis on, words as opposed to other parts of a theory or program; -- said of grammatical theories and computer programs, especially programs for understanding language.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• verb transitive To convert to a single lexical unit, as a group of words with meaning beyond their parts.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• verb make or coin into a word or accept a new word into the lexicon of a language