mainspring

• POS: Noun
• HYPHEN: main=spring

CIDE DICTIONARY

mainspring, n. 

 The principal or most important spring in a piece of mechanism, especially the moving spring of a watch or clock or the spring in a gunlock which impels the hammer.  [1913 Webster]

OXFORD DICTIONARY

mainspring, n.
1 the principal spring of a mechanical watch, clock, etc.
2 a chief motive power; an incentive.

THESAURUS

mainspring

ambition, aspiration, basis, calling, cause, consideration, font, fount, fountain, fountainhead, goal, ground, guiding light, guiding star, headspring, headstream, headwater, ideal, inspiration, intention, lodestar, matter, mine, motive, principle, quarry, reason, riverhead, sake, score, source, spring, springhead, ulterior motive, vocation, well, wellhead, wellspring

ROGET THESAURUS

mainspring

Motive

N motive, springs of action, wellsprings of action, reason, ground, call, principle, by end, by purpose, mainspring, primum mobile, keystone, the why and the wherefore, pro and con, reason why, secret motive, arriere pensee, intention, inducement, consideration, attraction, loadstone, magnet, magnetism, magnetic force, allectation, allective, temptation, enticement, agacerie, allurement, witchery, bewitchment, bewitchery, charm, spell, fascination, blandishment, cajolery, seduction, seducement, honeyed words, voice of the tempter, song of the Sirens forbidden fruit, golden apple, persuasibility, persuasibleness, attractability, impressibility, susceptibility, softness, persuasiveness, attractiveness, tantalization, influence, prompting, dictate, instance, impulse, impulsion, incitement, incitation, press, instigation, provocation, inspiration, persuasion, suasion, encouragement, advocacy, exhortation, advice, solicitation, lobbyism, pull, incentive, stimulus, spur, fillip, whip, goad, ankus, rowel, provocative, whet, dram, bribe, lure, decoy, decoy duck, bait, trail of a red herring, bribery and corruption, sop, sop for Cerberus, prompter, tempter, seducer, seductor, instigator, firebrand, incendiary, Siren, Circe, agent provocateur, lobbyist, impulsive, motive, suasive, suasory, persuasive, persuasory, hortative, hortatory, protreptical, inviting, tempting suasive, suasory, seductive, attractive, fascinating, provocative, induced, disposed, persuadable, spellbound, instinct with, smitten with, infatuated, inspired, by, because, therefore, from this motive, from that motive, for this reason, for that reason, for, by reason of, for the sake of, count of, out of, from, as, forasmuch as, for all the world, on principle, fax mentis incendium gloriae, temptation hath a music for all ears, to beguile many and be beguiled by one.

Instrument

N instrument, machinery, mechanism, engineering, instrument, organ, tool, implement, utensil, machine, engine, lathe, gin, mill, air engine, caloric engine, heat engine, gear, tackle, tackling, rig, rigging, apparatus, appliances, plant, materiel, harness, trappings, fittings, accouterments, barde, equipment, equipmentage, appointments, furniture, upholstery, chattels, paraphernalia, mechanical powers, lever, leverage, mechanical advantage, crow, crowbar, handspike, gavelock, jemmy, jimmy, arm, limb, wing, oar, paddle, pulley, wheel and axle, wheelwork, clockwork, wheels within wheels, pinion, crank, winch, cam, pedal, capstan, wheel, inclined plane, wedge, screw, spring, mainspring, can hook, glut, heald, heddle, jenny, parbuckle, sprag, water wheel, handle, hilt, haft, shaft, heft, shank, blade, trigger, tiller, helm, treadle, key, turnscrew, screwdriver, knocker, hammer, edge tool, borer, vice, teeth, nail, rope, peg, support, spoon, arms, oar, cardiograph, recapper, snowplow, tenpenny, votograph, instrumental, mechanical, machinal, brachial.

Cause

N cause, origin, source, principle, element, occasioner, prime mover, primum mobile, vera causa, author, mainspring, agent, leaven, groundwork, foundation, spring, fountain, well, font, fountainhead, spring head, wellhead, fons et origo, genesis, descent, remote cause, influence, pivot, hinge, turning point, lever, crux, fulcrum, key, proximate cause, causa causans, straw that breaks the camel's back, ground, reason, reason why, why and wherefore, rationale, occasion, derivation, final cause, les dessous des cartes, undercurrents, rudiment, egg, germ, embryo, bud, root, radix radical, etymon, nucleus, seed, stem, stock, stirps, trunk, tap-root, gemmule, radicle, semen, sperm, nest, cradle, nursery, womb, nidus, birthplace, hotbed, causality, causation, origination, production, caused, causal, original, primary, primitive, primordial, aboriginal, protogenal, radical, embryonic, embryotic, in embryo, in ovo, seminal, germinal, at the bottom of, connate, having a common origin, because, behind the scenes, causa latet vis est notissima, felix qui potuit rerum cognoscere causas.