It is coil containing many circular terns, there wire are wrapped closely in the shape of a cylinder and it is used as an electromagnet.

It also refers to any device that converts electrical energy to mechanical energy using a solenoid. The device creates a magnetic field from electric current and uses the magnetic field to create linear motion.

In above image :-

(1). The magnetic field for the current carrying solenoid 

(2). For bar magnet.

List of the distinguishing features between the two fields:

(a) The poles of the bar magnet do not lie exactly at the end of the magnet but are somewhat inside. In a solenoid, poles can be considered to be lying at the edge.

(b) The magnetism retains in the bar magnet naturally but in the solenoid, the magnetism is there so long current flows through it.

(c) A magnetic field of a bar magnet emanates from throughout the body of the magnet, with more intensity at the poles. While there is no field emanating from the lateral surface of the solenoid.