masc. proper name, from Old French Rogier, from Old High German Hrotger, literally "famous with the spear," from hruod- "fame, glory" + ger "spear" (see gar (n.)). As a generic name for "a person," attested from 1630s. Slang meaning "penis" was popular c.1650-c.1870; hence the slang verb sense of "to copulate with (a woman)," attested from 1711.
The use of the word in radio communication to mean "yes, I understand" is attested from 1941, from the U.S. military phonetic alphabet word for the letter -R-, in this case an abbreviation for "received." Said to have been used by the R.A.F. since 1938. The Jolly Roger pirate flag is first attested 1723, of unknown origin;