"defined category" is correct and usable in written English.
It is typically used when referencing a particular classification or type of something. For example, "Our school has a defined category of honors students."
Coasting schools aren't a clearly defined category.
It appears to refer to terrorist leaders, a poorly defined category.
The broadly defined category of touching with "the intention to commit an act of homosexuality" can also bring a sentence of up to seven years.
The Treasury method, apparently, is to invent a politically palatable phrase to describe an arbitrarily defined category of zombie-bank-balance-sheet complexity and then pretend that people have been deeply curious about this phrase for many months.
This all goes out the window for those who are convicted under a newly defined category of "serious organised crime" that casts a wider net than the traditional province of bikies.
Pullman and his fellow anti-age-labellers rightly argue that a child could be steered away from books he or she might naturally gravitate toward, or be made to feel insufficient by failure to fit in a narrowly defined category.
The topics generally fall into tightly defined categories.
(Ten years ago, the basis of star ratings started to shift from broader asset classes to more narrowly defined categories).
In March, he broke down for shareholders the various markets where Citi operates into four clearly defined categories.
In 1886 the Aborigines Protection Act defined categories of Aboriginal Australians and forced those of mixed ancestry off the reserves.
That same slippage between easily defined categories might be applied to many of the works at LongHouse.
