Tendons are cord-like structures which transmit muscular force to a bone. Though generally like long shiny cords, they can also be short, thick and flat. If you are looking at cuts of meat, tendons are best seen in the shank - the glistening slender things.
The term 'ligament' can be used in a variety of contexts. Most commonly, these are like tendons, but used to hold bones together. They are seen around joints.
Cartilage is a type of tissue which is tough almost like bone, but not hard like bone. However, it is tougher than tendon or ligament. Unlike tendon and ligament, cartilage can withstand a great degree of compression. In plain English, it is "gristle".