Space (4)
(Other definitions for area that I've seen before include "Geographical region" , "environs" , "Region; extent of a surface" , "Territory" , "'Tract, region (4)'" .)
'space' is the definition.
(enough space or room to do something)
This is all the clue.
(Other definitions for room that I've seen before include "Adequate space" , "Space; chamber" , "Enclosed space in a building" , "Chamber; scope" , "Enclosed part of building" .)
'space' is the definition.
(I know that gap is a type of space)
This is all the clue.
(Other definitions for gap that I've seen before include "A break or opening as in a hedge" , "Narrow opening" , "Pause" , "Opening, breach" , "Room" .)
'space' is the definition.
(I know that cavity is a type of space)
This is the entire clue.
(Other definitions for cavity that I've seen before include "Hollow space" , "A hole could mean work for the dentist" , "Hollow place" , "Small hole as in tooth" , "A hollow within a solid, say tooth" .)
(Other definitions for cadets that I've seen before include "Army officer trainees" , "Military trainees" , "Officers potentially" , "Pupils" , "Casted as young army men" .)
'space' is the definition.
(synonyms)
This is the entire clue.
(Other definitions for outer that I've seen before include "Away from the centre" , "Poor shot" , "Objective" , "This space is beyond earth's atmosphere" , "Outside; external" .)