SEMILUNAR a. 2 definitions
Shaped like a half moon. Semilunar bone (Anat.), a bone of the carpus; the lunar. See Lunar, n. -- Semilunar, or Sigmoid, valves (Anat.), the valves at the beginning of the aorta and of the pulmonary artery which prevent the blood from flowing back into the ventricle.
ALMANAC n.
s, etc. Nautical almanac, an almanac, or year book, containing astronomical calculations (lunar, stellar, etc.), and other information useful to mariners.
CAUSTIC; CAUSTICAL a.
sh, KOH, and soda, NaOH, or solutions of the same. -- Caustic silver, nitrate of silver, lunar caustic. -- Caustic surface (Optics), a surface to which rays reflected or refracted by another surface are tangents. Caustic curves and surfaces are called catacaustic when formed by reflection, and diacaustic when formed…