Restrictiveness
In semantics, a modifier is said to be
restrictive if it restricts the reference of its head. For example, in "the red car is fancier than the blue one",
red and
blue are restrictive, because they restrict which cars
car and
one are referring to. By contrast, in "John's beautiful mother",
beautiful is non-restrictive; "John's mother" identifies her sufficiently, while "beautiful" only serves to add more information. Restrictive modifiers are also called
defining,
identifying,
essential, or
necessary; non-restrictive ones are also called
non-defining,
non-identifying,
descriptive, or
unnecessary. In certain cases, generally when restrictiveness is marked syntactically through the lack of commas, restrictive modifiers are called
integrated and non-restrictive ones are called
non-integrated or
supplementary.