from The American Heritage® Dictionary of the English Language, 4th Edition
- transitive v. To make or become longer.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- v. To make longer, to extend the length of.
- v. To become longer.
from the GNU version of the Collaborative International Dictionary of English
- transitive v. To extent in length; to make longer in extent or duration
- intransitive v. To become longer.
from The Century Dictionary and Cyclopedia
- To make long or longer; extend or elongate in space or in duration; protract or prolong: as, to lengthen a line; to lengthen life; to lengthen a vowel or syllable in pronunciation.
- To grow long or longer; extend in length.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- v. become long or longer
- v. make longer
length + -en (Wiktionary)