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 let out his breath in a long sigh.
PHRASAL VERB : V n P , V P n (not pron)
2.
If you let out a particular sound, you make that sound. ( WRITTEN )
When she saw him, she let out a cry of horror.
= give out
PHRASAL VERB : V P n (not pron) , also V n P
3.
see also let 14