O'Sullivan & Hilliard's The Law of Contract (2018 8 ed). 16.23 starts on p. 387, 16.35 on p. 391.
Right: Pindyck, Rubinfeld. Microeconomics, Global Edition (2017 9 ed). p. 152.
I'm not a microeconomist, but these terms appear to be defined wholly differently? Or am I overlooking something similar that underlies them?