Decreasing

Hi there. An apparently easy question but is decreasing the same as knitting 2 together? This is an instruction for middle
Of row. Many thanks. Cariline

K2tog is one example of a decrease.
When you knit 2 together you decrease one stitch. The decrease slants to the right. There are other ways to decrease, too. The ssk decreases one stitch and slants to the left. Here are several decreases. Try them out on a swatch just to see how they are worked.
http://www.knittinghelp.com/videos/decreases