'tauten' definitions:

Definition of 'tauten'

(from WordNet)
verb
Become taut or tauter; "Your muscles will firm when you exercise regularly"; "the rope tautened" [syn: tauten, firm]
verb
Make taut or tauter; "tauten a rope" [syn: tauten, firm]

Synonyms of 'tauten'

From: Moby Thesaurus