mid-15c., a term in logic, "that which is said of a subject," from Old French predicat and directly from Medieval Latin predicatum, from Latin praedicatum "that which is said of the subject," noun use of neuter past participle of praedicare "assert, proclaim, declare publicly," from prae- "forth, before" (see pre-) + dicare "proclaim" (from PIE root *deik- "to show," also "pronounce solemnly," and see diction).
The grammatical sense of "the word or words which express what is said of a subject in a proposition" is from 1630s. Related: Predicative; predicator; predicatory.
"belonging to a predicate; constituting a part of what is asserted of anything," 1887, from Latin praedicatus, past participle of praedicare "proclaim, announce" (see predicate (n.)).
"declare, assert, affirm," especially as an attribute or quality of something, 1550s, a back formation from predication, or else from Latin praedicatus, past participle of praedicare "proclaim, announce" (see predicate (n.)). Related: Predicated; predicating. Phrase predicated on "founded on, based on," is American English, recorded from 1766.