Latin, literally "in the midst of things," from medias, accusative fem. plural of medius "middle" (see medial (adj.)) + accusative plural of res "a thing" (see re). From Horace, in reference to narrative technique:

Semper ad eventum festinat, et in medias res,

Non secus ac notas auditorem rapit (etc.)

a puzzle or riddle consisting of words or phrases represented by pictures of objects whose names resemble in sound the words or phrases intended, c. 1600, apparently from Latin rebus (and meaning literally "by means of objects"), ablative plural of res "thing, object" (see re). According to French sources (Gilles Ménage, "Les origines de la langue françoise," 1650), principally from the phrase de rebus quæ geruntur "of things which are going on," in reference to the satirical pieces composed by Picardy clerks at carnivals, subtle satires of current events using pictures to suggest words, phrases or things. Or this use of the Latin word might be from the representations being non verbis sed rebus "not by words, but by things."

1846, "mental act of materializing (a person or concept), objectivization, the regarding or treating of an idea as a thing," from Latin re-, stem of res "thing" (see re), + -fication "a making or causing." In Marxist writing, "depersonalization," translating German Verdinglichung.

"make mentally into a thing; make (an abstraction) real or material; consider as a thing," 1854, a back-formation from reification or else from re-, stem of Latin res "thing, object; matter, affair, event; circumstance, condition" (see re) + -fy. Related: Reified; reifying.

"state in which supreme or executive power rests in the people via representatives chosen by citizens entitled to vote," c. 1600, from French république (15c.), from Latin respublica (ablative republica) "the common weal, a commonwealth, state, republic," literally res publica "public interest, the state," from res "affair, matter, thing" (see re) + publica, fem. of publicus "public" (see public (adj.)).

Applied to particular states so constituted by 1630s. The notion of "community in which there is a certain equality of members" is behind such expressions as republic of letters "collective body of those engaged in literary pursuits," attested from 1702.

Latin word once used in various phrases in English, often in legal language, where it means "the condition of something, the matter in hand or point at issue;" literally "thing" (see re). For example res ipsa loquitur "the thing speaks for itself;" res judicata "a point decided by competent authority."