Cancel  v. (-ll-; us -l-) 1 revoke or discontinue (an arrangement). 2 delete (writing etc.). 3 mark (a ticket, stamp, etc.) To invalidate it. 4 annul; make void. 5 (often foll. By out) neutralize or counterbalance. 6 math. Strike out (an equal factor) on each side of an equation etc.  cancellation n. [latin: related to *chancel]