let out that dress--I gained a lot of weight.    From Wordnet, Princeton University. 

She let out a big heavy sigh.    From Wordnet, Princeton University. 

Verb (used with object) : to let him escape. ,to let us through. ,to let work to a carpenter. ,to let one know the truth. ,Let me see. Let us go. Just let them try it!.    From Dictionary.com.