1) Banker's discount is interest charged on the face value of a bill of exchange for the period between the date the bill is discounted by a banker and the legally due date. 2) True discount is the interest charged on the amount received by the holder of the bill for the unexpired period to the legally due date. 3) Banker's gain is the difference between the banker's discount and true discount. It represents the interest earned by the banker on the true discount amount.