*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."
c. 1300, restoren, "to give back," also, "to build up again, repair; renew, re-establish; free from the effects of sin; bring back to a former and better state," from Old French restorer, from Latin restaurare "repair, rebuild, renew." This is from re- "back, again" (see re-) + -staurare, not attested by itself but also in instaurare "to set up, establish; renew, restore," etc., from PIE root *sta- "to stand, make or be firm."
From late 14c. as "to cure, heal, bring back to a vigorous state;" of objects, beliefs, etc., "bring back to an original state or condition," 1670s. Related: Restored; restoring.
1650s, "a making or becoming better," from French amélioration, from Old French ameillorer (12c.), from a "to" (see ad-) + meillior (Modern French meìlleur) "to better, repair, improve," from Late Latin meliorare "improve," from Latin melior "better," perhaps originally "stronger" (from PIE root *mel- (2) "strong, great").