WordNet sense 1 (an unbroken period of time during which you do something):

stint

WordNet sense 2 (the capacity for being stretched):

stretchability, stretchiness

WordNet sense 3 (occupy a large, elongated area):

stretch along

WordNet sense 4 (extend or stretch out to a greater or the full length):

extend, unfold, stretch out

WordNet sense 5 (capable of resuming original shape after stretching or compression; springy):

elastic

WordNet sense 6 (exercise designed to extend the limbs and muscles to their full extent):

stretching

WordNet sense 7 (corrupt, debase, or make impure by adding a foreign or inferior substance; often by replacing valuable ingredients with inferior ones):

adulterate, debase, dilute, adulterate

WordNet sense 8 (the act of physically reaching or thrusting out):

reach, reaching

WordNet sense 9 (make long or longer by pulling and stretching):

elongate