mid-15c., from Scottish, from Old Celtic bardos "poet, singer," from PIE root *gwer- "to lift up the voice, praise." In historical times, a term of contempt among the Scots (who considered them itinerant troublemakers), but one of great respect among the Welsh.
All vagabundis, fulis, bardis, scudlaris, and siclike idill pepill, sall be brint on the cheek. [local Scottish ordinance, c.1500]Subsequently idealized by Scott in the more ancient sense of "lyric poet, singer." Poetic use of the word in English is from Greek bardos, Latin bardus, both from Gaulish.