ray [reı] n
[Sense: 1-5; Date: 1300-1400; : Old French; Origin: rai, from Latin radius; RADIUS]
[Sense: 6; Date: 1300-1400; : Old French; Origin: raie, from Latin raia]
1.) a straight narrow beam of light from the sun or moon
The room darkened as a cloud hid the sun's rays.
ray of
Rays of light filtered through the trees.
2.) a beam of heat, electricity, or other form of energy
→↑cosmic ray, gamma ray, x-ray1
3.) a ray of hope/light etc
something that provides a small amount of hope or happiness in a difficult situation
a treatment that offers a ray of hope for cancer sufferers
4.) a ray of sunshine
someone who is happy and makes a difficult situation seem better
5.) catch some/a few rays informal
to sit or lie in the sun
Let's go out and catch a few rays.
6.) a large flat sea fish with a long pointed tail

Dictionary of contemporary English. 2013.