Tail

First, it is used to describe the rear end of an animal's body, especially when it forms a distinct, flexible appendage to the trunk. It is the part of the body that roughly corresponds to the sacrum and coccyx in mammals and birds. Its uses include locomotion (e.g. fish), balance (e.g. cat), grasping (e.g. monkey), social signals (dog), defense.

It can also describe anything like an animal's tail in form or position, such as the tail of a shirt.

A tail is also the luminous train behind a comet or meteor, or a train of attendants or followers. (See retinue[?].)

The obverse side of a coin is called the tails side.

A long braid or tress of hair is sometimes called a tail, although queue is probably a better description.

A tail can be the rear or back section of an aircraft or missile.

A tuxedo jacket is sometimes referred to as "tails" if the bottom part of the jacket is in the shape of a penguin's backside.

To tail someone in surveillance is to follow that person stealthily.

In the Unix operating system, the tail command provides the last few lines of a file.