Is hand translucent?

Translucent since it is possible to monitor blood flow and pulse rate by placing a light source and photo detector either side of a finger. Opaque means totally barring the passage of light.

Uhm, the definition of translucent is "allowing light to pass through diffusely," so I guess most hand sanitizers are translucent since if you drip some on a window the light will go through...

That I believe is clasping.

I think there is a very subtle difference. hand and hand just refers to two hands not necessarily together.hand in hand implies that the hands are connected or together.

hand in hand is when two people are holding each others hands tight.