single (adj.) Look up single at Dictionary.com
early 14c., "unmarried," from Old French sengle, sangle "alone, unaccompanied; simple, unadorned," from Latin singulus "one, one to each, individual, separate" (usually in plural singuli "one by one"), from sim- (stem of simplus; see simple) + diminutive suffix. Meaning "consisting of one unit, individual, unaccompanied by others" is from late 14c. Meaning "undivided" is from 1580s. Single-parent (adj.) is attested from 1966.
single (n.) Look up single at Dictionary.com
c.1400, "unmarried person," mid-15c., "a person alone, an individual," from single (adj.). Given various technical meanings from 16c. Sports sense is attested from 1851 (cricket), 1858 (baseball). Of single things from 1640s. Meaning "one-dollar bill" is from 1936. Meaning "phonograph record with one song on each side" is from 1949. Meaning "unmarried swinger" is from 1964; singles bar attested from 1969. An earlier modern word for "unmarried or unattached person" is singleton (1937).
single (v.) Look up single at Dictionary.com
"to separate from the herd" (originally in deer-hunting, often with forth or out), 1570s, from single (adj.). Baseball sense of "to make a one-base hit" is from 1899 (from the noun meaning "one-base hit," attested from 1858). Related: Singled; singling.