What's the difference between transparent and translucent?

According to a dictionary, transparent allows light to pass through without diffusion whilie translucent with diffusion.

Can you either one to describe glowing skin?

That's a good dictionary. When it passes without diffusion the arrangement of the light rays is not disturbed, so an image may pass through a transparent object without distortion. "Frosted" glass would be a translucent object. The light passes through but you have no idea what's on the other side of the glass.

Of course it's not all black and white. There are varying degrees of distortion.
"Translucent" is often used to describe skin. Transparent skin would be kind of horrible Emotion: smile
Students: We have free audio pronunciation exercises.
If a person is describe to have translucent skin, does it mean you can kind of see the nerves or does it mean the skin glows?
It means the skin looks as though light would shine through it.
People have teased me that I am so white that I'm clear. In fact, if you look at my inner arm, you can see veins with a shocking degree of clarity. It's quite translucent. However, it's not transparent - that would be as though I had plastic wrap for skin.

I would not describe "glowing" skin as being translucent. Only lizzard-belly white people like me.
Students: Are you brave enough to let our tutors analyse your pronunciation?
GG, the dictionary agrees with you, but I think the word is starting to be thrown around rather loosely. It seems to be getting confused with having "clear" skin, in the sense of not having blemishes. So we have products promising to improve "skin clarity" and give us beautiful, translucent skin. Adding to the confusion is "translucent powder" which has been around for quite a while.
http://www.lumene.com/default.asp?docId=14091 (only one example)
Is that why you like elephants, GG?