Imprisonment is a legal term.
The book Termes de la Ley contains the following definition:
Imprisonment is no other thing than the restraint of a man's liberty, whether it be in the open field, or in the stocks, or in the cage in the streets or in a man's own house, as well as in the common gaols; and in all the places the party so restrained is said to be a prisoner so long as he hath not his liberty freely to go at all times to all places whither he will without bail or mainprise or otherwise.[1]
This passage was approved by Atkin and Duke LJJ in Meering v Grahame White Aviation Co.[2]
See also Bird v Jones (1845) 7 QB 742, (1845) 115 ER 668, (1845) 15 LJQB 82, (1845) 9 Jur 870, (1845) 10 JP 4, (1845) 5 LT (OS) 406.
Imprisonment without lawful cause is a tort called false imprisonment.[3]
Imprisonment is a type of sentence.[4]