OPERA n. 3 definitions
drama, either tragic or comic, of which music forms an essential part; a drama wholly or mostly sung, consisting of recitative, arials, choruses, duets, trios, etc., with orchestral accompaniment, preludes, and interludes, together with appropriate costumes, scenery, and action; a lyric drama.
OPTIC; OPTICAL a. 3 definitions
erior surfaces. In a normal eye it is in the direction of the optic axis that objects are most distinctly seen. (b) The line in a doubly refracting crystal, in the direction of which no double refraction occurs. A uniaxial crystal has one such line, a biaxial crystal has two. -- Optical circle (Opt.), a graduated circ…
OSMIC a.
d osmites. -- Osmic tetroxide (Chem.), a white volatile crystalline substance, OsO4, the most stable and characteristic of the compounds of osmium. It has a burning taste, and gives off a vapor, which is a powerful irritant poison, violently attacking the eyes, and emitting a strong chlorinelike odor. Formerly imprope…
OSMUND n.
A fern of the genus Osmunda, or flowering fern. The most remarkable species is the osmund royal, or royal fern (Osmunda regalis), which grows in wet or boggy places, and has large bipinnate fronds, often with a panicle of capsules at the top. The rootstock contains much starch, and has been used in stiffening linen.…