Stories We Like: A Guide to the Comma
early 14c., "hard, resinous mineral pitch found originally in Biblical lands," from Late Latin asphaltum, from Greek asphaltos "asphalt, bitumen," probably from a non-Greek source, possibly Semitic [Klein, citing Lewy, 1895]. Another theory holds it to be from Greek a- "not" + *sphaltos "able to be thrown down," taken as verbal adjective of sphallein "to throw down," in reference to a use of the material in building.
Meaning "paving composition" dates from 1847 and its popular use in this sense established the modern form of the English word, mostly displacing asphaltum, asphaltos. As a verb meaning "to cover with asphalt," from 1872.