Shaped like a half-moon; crescent-shaped.(adjective)
American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Use "semilunar" in a sentence
"Oh no! but what dull ache is this in that obscurely sensitive region, somewhere below the heart, where the nervous centre called the semilunar ganglion lies unconscious of itself until a great grief or a mastering anxiety reaches it through all the non-conductors which isolate it from ordinary impressions?"
"The memory effect occurred because of a rare type of brain cell called semilunar granule cells, described in 1893 by the father of neuroscience, Ramón y Cajal."
"The aperture leading from the left ventricle to the aorta is guarded by three crescentric flaps -- called the "semilunar" valves of the aorta."