The Collaborative International Dictionary of English v.0.48:
Strengthener \Strength"en*er\, n. One who, or that which, gives or adds strength. --Sir W. Temple. [1913 Webster]WordNet (r) 3.0 (2006):
strengthener n 1: a device designed to provide additional strength; "the cardboard backing was just a strengthener"; "he used gummed reinforcements to hold the page in his notebook" [syn: strengthener, reinforcement]