A knitter makes use of short rows in order to add shaping to a garment. Where Increasing and Decreasing can make columns of stitches that do not exist for the entire height of a piece, short rows can make rows that do not exist for the entire width of the piece.
Several related techniques exist for creating short rows, but the simplest is as follows: Starting at the right edge of the piece, on the right side, knit across to the left side of the area to get the short rows, and stop. Wrap and turn, and on the wrong side of the piece, purl back to the other end of the short row region. Wrap and turn again, and on the right side of the piece, knit all the way over to the left edge of the piece. Inside the short-row region, there are now three new rows, while outside that region, there is just one.
Two common uses of short rows are in bust shaping and in stocking heels.