A bow is a special kind of pretty knot that leaves two big loops, and is usually made of ribbon in hair ties or on a dress. You often see bows at Christmas time as decorations or on presents.
A bow is a weapon that is used to fire arrows at a target. Someone who uses a bow and arrows is called an archer. A bow can be used for hunting animals, target practise for sport, or as a weapon in war.
Bowing is a way of greeting or acknowledging someone, or a mark of respect. You bow by lowering the top half of your body. In some countries, you can bow just by lowering your head.