Averechts means 'not right'. It's used in knitting for the purl stitch; in stockinette stitch (the stitch most people associate with knitted fabric), you knit rechts on the 'right' side, and averechts on the 'wrong' side. It also has meanings like 'against the grain', 'in the wrong direction' and contrary.

This not necessarily reliable source claims that 'ave' meant 'away from' in Middle Dutch.