The word that started it all, the verb knit has been used in English since about 1000 AD. It derived from the Old English word cnyttan, which means "to tie in a knot," which was its first meaning. By the 1300s, the verb referred to tying string or thread into a net, and in 1530, we have our first use of knit to refer to the creation of an object by weaving together a series of interlocking loops using two needles ("I knyt bonettes or hosen.")
From the verb, we get the noun knit showing up in the late 1500s. It initially referred to a knit stitch, one of the two foundation stitches that make up all knitting (as in, "work in knit for two rows"), then came to be used for knitted fabric ("knit stretches more than lawn") and items made by knitting ("hand-wash delicate knits").