When Stevie Ray Vaughan introduced "Double Trouble", he alway said, "Tommy Shannon on the Fender Bass"...Probably just terminology overlap/transition from that 50's/60's recording industry designation. In the 50's there was "bass" (upright), "tic-tac bass" (Dano Baritone guitar), and "Fender bass"(electric bass), and though the 60's just "Fender bass". Once many more basses were used in recordings and live in the late 60's -70's the old-school term just faded away.
