apparatus n.

word-forming element expressing direction toward or in addition to, from Latin ad "to, toward" in space or time; "with regard to, in relation to," as a prefix, sometimes merely emphatic, from PIE root *ad- "to, near, at."

Simplified to a- before sc-, sp- and st-; modified to ac- before many consonants and then re-spelled af-, ag-, al-, etc., in conformity with the following consonant (as in affection, aggression). Also compare ap- (1).

In Old French, reduced to a- in all cases (an evolution already underway in Merovingian Latin), but French refashioned its written forms on the Latin model in 14c., and English did likewise 15c. in words it had picked up from Old French. In many cases pronunciation followed the shift.

Over-correction at the end of the Middle Ages in French and then English "restored" the -d- or a doubled consonant to some words that never had it (accursed, afford). The process went further in England than in France (where the vernacular sometimes resisted the pedantic), resulting in English adjourn, advance, address, advertisement (Modern French ajourner, avancer, adresser, avertissement). In modern word-formation sometimes ad- and ab- are regarded as opposites, but this was not in classical Latin.

*perə-, Proto-Indo-European root meaning "to produce, procure" and yielding and derived words in diverse senses; possibly related to *pere- (2) "to grant, allot."

It forms all or part of: ante-partum; apparatus; apparel; biparous; disparate; emperor; empire; heifer; imperative; imperator; imperial; juniper; multiparous; nulliparous; oviparous; para- (2) "defense, protection against; that which protects from;" Parabellum; parachute; parade; parados; parapet; parasol; pare; parent; -parous; parry; parturient; poor; post-partum; preparation; prepare; primipara; puerperal; rampart; repair (v.1) "to mend, put back in order;" repertory; separate; sever; several; spar (v.); viper; vituperation; viviparous.

It is the hypothetical source of/evidence for its existence is provided by: Sanskrit prthukah "child, calf, young of an animal;" Greek poris "calf, bull;" Latin parare "make ready, prepare," parire "produce, bring forth, give birth to;" Czech spratek "brat, urchin, premature calf;" Lithuanian periu, perėti "to brood;" Old High German farro, German Farre "bullock," Old English fearr "bull."