Early 18th century. From classical Latin proceleusmaticus, designating a metrical foot of four short syllables, (noun) foot of four short syllables from Hellenistic Greek προκελευσματικός, designating a metrical foot of four short syllables, (noun) foot of four short syllables from ancient Greek προ- + κέλευσματ-, κέλευσμα (also κέλευμα) celeusma + -ικός, after Hellenistic Greek προκελεύειν to give orders beforehand.