Hyaline

a. [Lat. hyalinus, Gr. ὑάλινος, from ὕαλος, glass; Fr. hyalin.] Glassy; resembling glass; consisting of glass; crystalline; transparent. “Hyaline spaces.” Carpenter.

n. 1. The glassy surface of the sea. “The clear hyaline, the glassy sea.” Milton. Our blood runs amazed 'neath the calm hyaline. Browning. 2. (Embryogeny.) The pellucid substance in cells in process of development.