Substitutus

Substitutus is a Latin term, predominantly encountered in scholarly writing, that functions as the perfect passive participle meaning "substituted" or as an adjective describing something that has undergone substitution or replacement. In modern usage it is not a fixed technical term but appears as a descriptive label in various disciplines.

Etymology: From Latin substituere "to substitute," with the perfect passive participle substitutus. The form is historically common in manuscripts, scholia, and early critical works to denote a variant or substituted element, sometimes annotated as "substitutus" to distinguish from the original.

Textual criticism and linguistics: In textual criticism, substitutus can designate a form or reading introduced by substitution rather than preservation of the original text. In linguistics or philology, it may describe a substituted form in derivations or sound changes, where a phoneme or morpheme is replaced by another under a rule.

Science and logic: In older chemical or philosophical literature, substituted compounds or terms may be described with the adjective substitutus to mark the result of a substitution reaction or a definitional replacement. In logic and mathematics, substitution is a fundamental operation, and a discussion of substitutus may appear in historical expositions to refer to the replaced term or variable.

See also: substitution, substitution reaction, substituent, textual criticism, variant.