1.
If something or someone lets water, air, or breath out, they allow it to flow out or escape.
It lets sunlight in but doesn’t let heat out...
Meer ~ his breath in a long sigh.
PHRASAL VERB: V n P, V P n (not pron)
2.
If you ~ a particular sound, you make that sound. (WRITTEN)
When she saw him, she ~ a cry of horror.
= give out
PHRASAL VERB: V P n (not pron), also V n P
3.
see also let 14