The extent to which something is stretchable(noun)
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Use "stretchability" in a sentence
"Reading between the lines, it seemed that Kiper then sort of tipped his cap to Holt, conceding that perhaps Williamson would give the Vikings "big-time vertical stretchability.""
"Muslin's the traditional test material, but if your beloved fabric is a knit, for example, you'll want to test the pattern first in a knit with the same stretchability."
"I'm making this one in 2 x 2 rib which I like a lot for its stretchability."