n.
1.a particular geographical region of indefinite boundary (usually serving some special purpose or distinguished by its people or culture or geography)
2.a particular environment or walk of life
3.a subject of study
4.a part of a structure having some specific characteristic or function
5.a part of an animal that has a special function or is supplied by a given artery or nerve
6.the extent of a 2-dimensional surface enclosed within a boundary
Idiom of the Day
put down (an airplane) or put (an airplane) down
to land an aircraft
The pilot put down the airplane very gently when they reached the airport.
