Old English fullfyllan "fill up" (a room, a ship, etc.), "make full; take the place of (something)," from full (adj.), here perhaps with a sense of "completion" + fyllan (see fill (v.), which is ultimately from the same root).
It was used from mid-13c. in reference to prophecy (probably translating Latin implere, adimplere). From mid-13c. as "do, perform; carry out, consummate, carry into effect;" from c. 1300 as "complete, finish; satiate, satisfy, gratify." Related: Fulfilled; fulfilling.
Modern English combinations with full tend to have it at the end of the word (as -ful), but this is a recent development and in Old English it was more common at the start, but this word and fulsome appear to be the only survivors.
Self-fulfilling prophecy is attested by 1949, associated with and popularized by U.S. sociologist Robert K. Merton, in writings on racial prejudices, who described it as a false definition of a situation at the outset that evokes a behavior which seems to validate the false concept.
Proto-Indo-European root meaning "one; as one, together with."
It forms all or part of: anomalous; anomaly; assemble; assimilate; ensemble; facsimile; fulsome; hamadryad; haplo-; haploid; hendeca-; hendiadys; henotheism; hetero-; heterodox; heterosexual; homeo-; homeopathy; homeostasis; homily; homo- (1) "same, the same, equal, like;" homogenous; homoiousian; homologous; homonym; homophone; homosexual; hyphen; resemble; same; samizdat; samovar; samsara; sangha; Sanskrit; seem; seemly; semper-; sempiternal; similar; simple; simplex; simplicity; simulacrum; simulate; simulation; simultaneous; single; singlet; singular; some; -some (1); -some (2); verisimilitude.
It is the hypothetical source of/evidence for its existence is provided by: Sanskrit sam "together," samah "even, level, similar, identical;" Avestan hama "similar, the same;" Greek hama "together with, at the same time," homos "one and the same," homios "like, resembling," homalos "even;" Latin similis "like;" Old Irish samail "likeness;" Old Church Slavonic samu "himself."
early 14c., "plane figure having four equal sides and two acute and two obtuse angles," from Old French losenge "rhombus shape, diamond-shape" (as an ornamental motif in heraldry, etc.); "small square cake; windowpane," etc., a word used for many flat quadrilateral things (Modern French losange). It has cognates in Spanish losange, Catalan llosange, Italian lozanga, but the origin is disputed.
Probably from a pre-Roman Celtic language, perhaps Iberian *lausa or Gaulish *lausa "flat stone" (compare Provençal lausa, Spanish losa, Catalan llosa, Portuguese lousa "slab, tombstone"). From late 14c. as "diamond-shaped cake or wafer;" specific sense "small cake or tablet (originally diamond-shaped) of medicine and sugar, etc., meant to be held in the mouth and dissolved" is from 1520s.
The related words in Continental languages often have a sense "flattery, deceit" (compare Old French losengier "to praise unduly," losenge "flattery, false praise; deceitful friendliness"), which comes probably via the notion of square flat slabs of tombstones and their fulsome epithets. Some of this made its way into Middle English via French. Chaucer uses losenger "flatterer, deceiver;" losengerye "flattery."