فالخاص: لفظ وضع لمعنى معلوم، أو لمسمى معلوم على الانفراد
A specific expression is a word assigned to a known meaning or known referent individually.
Lafẓ is the expression; waḍʿ is its linguistic assignment; maʿlūm indicates a determined sense or referent; and ʿalā al-infirād marks its individual denotation rather than an open-ended collection of persons.
Specific does not mean only a proper personal name. In this classification, a named type or genus can also count as a specific expression.