"thin piece of wood," c. 1200, scincle, from Late Latin scindula (also the source of German Schindel), altered (by influence of Greek schidax "lath" or schindalmos "splinter") from Latin scandula "roof tile," from scindere "to cut, rend, tear asunder, split; split up, part, divide, separate," from PIE *skind-, from root *skei- "to cut, split." Meaning "small signboard" is first attested 1842. Sense of "woman's short haircut" is from 1924; the verb meaning "to cut the hair so as to give the impression of overlapping shingles" is from 1857.
"loose stones on a seashore," 1510s, probably related to Norwegian singl "small stones," or North Frisian singel "gravel," both said to be echoic of the sound of water running over pebbles.
"cover with shingles" (of houses), 1560s, from shingle (n.). Related: Shingled; shingling.