What is the name of the short cord that attaches a fly to a line in fishing?

Answer 1

A leader.

A leader can also be made up of a section of heavier monofilament (usually 8 to 9 feet) and then about 6 to 8 inches of smaller diameter length of monofilament, called "tippet" is then attached to the end of the leader. The fly would be attached to the tippet.

Answer 2

At the end of every fly line is attached a piece of monofilament called a leader. Attached to the end of a leader is a shorter and thinner piece of mono called tippet. Together, they form a way to transmit the kinetic energy from casting a weighted fly line down the monofilament to the fly. This transition occurs because of the change in diameter and weight from the fly line to the fly. A perfect leader is able to turn over the fly and deliver it accurately to its target.

Leaders comes in a variety of tensile strengths and lengths. A typical trout leader is longer, anywhere from 7 ft. to 15 ft. in length. Trout leaders are longer and their taper is more gradual because trout flies are smaller. Therefore, the tipper attached the end of a trout leader is also small. If you are throwing heavier flies, like streamers, leaders can be much shorter and heavier in tensile strength in order to turn over and cast heavier flies. Properly matching your leader to the correct fly fishing situation will make your fishing trip more successful.