"Reread through the manual until the instructions are crystal clear in your head.; The picture on this TV is crystal clear – you can see every grain of sand!"
2.AdjectiveWithout ambiguity or doubt; completely understood.
"Reread through the manual until the instructions are crystal clear in your head."
3.AdjectiveVisually clear, a sharp image, of high acuity.
"The picture on this TV is crystal clear – you can see every grain of sand!"