Precursor

Noun

 * 1) That which precurses, a forerunner, a predecessor, an indicator of approaching events.
 * 2)  One of the compounds that participates in the chemical reaction that produces another compound.

Thesaurus
advance guard, agent, airhead, alterant, alterative, alterer, ancestor, ancestors, announcer, antecedence, antecedency, antecedent, anteposition, anteriority, apprentice, architect, artificer, artist, author, avant-garde, battle line, beachhead, begetter, beginner, bridgehead, buccinator novi temporis, builder, catalyst, catalytic agent, colonial, colonist, colonizer, conceiver, constructor, craftsman, creator, danger sign, designer, deviser, discoverer, dominion, early bird, early comer, early riser, early symptom, effector, engenderer, engineer, executor, executrix, falling barometer, farthest outpost, father, ferment, first arrival, first line, forefront, foregoer, foregoing, forerunner, foreshadower, founder, front, front line, front position, front rank, front-runner, gathering clouds, generator, grower, harbinger, heading, herald, high sign, homesteader, immigrant, inaugurator, industrialist, initiator, innovationist, innovator, instigator, institutor, introducer, inventor, journeyman, le pas, leading, leaven, line, maker, manufacturer, master, master craftsman, messenger, modificator, modifier, mother, nester, omen, organizer, originator, outguard, outpost, outrider, past master, pioneer, planner, planter, point, precedence, precedency, precedent, preceding, precession, predecessor, preference, prefixation, preliminary sign, prelude, premise, premonitor, premonitory sign, premonitory symptom, presager, prime mover, priority, prodroma, prodrome, producer, prothesis, prototype, quarantine flag, railhead, raiser, realizer, red flag, red light, scout, settler, shaper, sire, skull and crossbones, smith, sooner, spearhead, squatter, storm petrel, stormy petrel, superiority, symptom, the lead, thundercloud, thunderhead, top priority, transformer, transmogrifier, urgency, van, vanguard, warning sign, warning signal, wright, yeast, yellow flag, yellow jack

Etymology
From praecursor:

Translations

 * Czech:
 * Dutch:
 * French:


 * German: Vorzeichen
 * Hungarian:
 * Japanese: 前兆 (ぜんちょう, zenchō), 先駆者 (せんくしゃ, senkusha)
 * Polish: prekursor


 * Finnish: esiaste
 * French: ,
 * German:


 * Hungarian: prekurzor
 * Japanese: 前駆物質 (ぜんくぶっしつ, zenku-busshitu), 前駆体 (ぜんくたい, zenku-tai)

Anagrams

 * procurers

Adjective

 * 1) precursory, preceding

Noun

 * 1) precursor