from The American Heritage® Dictionary of the English Language, 4th Edition
- transitive v. To make strong or increase the strength of.
- intransitive v. To become strong or stronger.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- v. To make strong or stronger; to add strength to; to increase the strength of; to fortify; to reinforce.
- v. To animate; to give moral strength to; to encourage; to fix in resolution; to hearten.
- v. To augment; to improve; to intensify.
- v. To grow strong or stronger.
from the GNU version of the Collaborative International Dictionary of English
- transitive v. To make strong or stronger; to add strength to.
- transitive v. To animate; to encourage; to fix in resolution.
- intransitive v. To grow strong or stronger.
from The Century Dictionary and Cyclopedia
- To make strong or stronger; add strength to, either physical, legal, or moral; confirm; establish: as, to strengthen a limb; to strengthen an obligation; to strengthen a claim; to strengthen authority.
- Synonyms To invigorate, fortify, brace, nerve, steel, corroborate, support, heighten.
- To grow strong or stronger.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- v. gain strength
- v. give a healthy elasticity to
- v. make strong or stronger
strength + -en (Wiktionary)