Grins at rays (5)
I believe the answer is:
beams
This could be a double definition.
'grins' is the first definition.
The answer and definition can be both related to communication as well as being plural nouns.
Perhaps they are linked in a way I don't understand?
'rays' is the second definition.
('beam' can be a synonym of 'ray')
'at' acts as a link.
Can you help me to learn more?
(Other definitions for beams that I've seen before include "Smiles; joists" , "Rays of light" , "Smiles broadly or sunnily" , "Shines" .)