pellucid
/pɛˈluːsɪd/Definitions
1. adjective
Transparent or able to be seen through; having a clear and unobstructed view.
“The pellucid waters of the lake were perfect for snorkeling.”
2. noun
A glass or optical instrument designed for observing objects that are too small or distant to be seen clearly by the naked eye.
“The astronomer used a pellucid to study the distant galaxies.”