1.  To get, as profit or advantage; to obtain or acquire by effort or labor; as, to gain a good living. [1913 Webster]
"What is a man profited, if he shall gain the whole world, and lose his own soul?" [1913 Webster]
"To gain dominion, or to keep it gained." [1913 Webster]
"For fame with toil we gain, but lose with ease." [1913 Webster]

2.  To come off winner or victor in; to be successful in; to obtain by competition; as, to gain a battle; to gain a case at law; to gain a prize. [1913 Webster]

3.  To draw into any interest or party; to win to one's side; to conciliate. [1913 Webster]
"If he shall hear thee, thou hast gained thy brother." [1913 Webster]
"To gratify the queen, and gained the court." [1913 Webster]

4.  To reach; to attain to; to arrive at; as, to gain the top of a mountain; to gain a good harbor. [1913 Webster]
"Forded Usk and gained the wood." [1913 Webster]

5.  To get, incur, or receive, as loss, harm, or damage. [1913 Webster]
"Ye should . . . not have loosed from Crete, and to have gained this harm and loss." [1913 Webster]

   To have or receive advantage or profit; to acquire gain; to grow rich; to advance in interest, health, or happiness; to make progress; as, the sick man gains daily. [1913 Webster]
"Thou hast greedily gained of thy neighbors by extortion." [1913 Webster]
"The English have not only gained upon the Venetians in the Levant, but have their cloth in Venice itself." [1913 Webster]
"My good behavior had so far gained on the emperor, that I began to conceive hopes of liberty." [1913 Webster]

gain, v. & n.
--v.
1 tr. obtain or secure (usu. something desired or favourable) (gain an advantage; gain recognition).
2 tr. acquire (a sum) as profits or as a result of changed conditions; earn.
3 tr. obtain as an increment or addition (gain momentum; gain weight).
4 tr. a win (a victory). b reclaim (land from the sea).
5 intr. (foll. by in) make a specified advance or improvement (gained in stature).
6 intr. & tr. (of a clock etc.) become fast, or be fast by (a specified amount of time).
7 intr. (often foll. by on, upon) come closer to a person or thing pursued.
8 tr. a bring over to one's interest or views. b (foll. by over) win by persuasion etc.
9 tr. reach or arrive at (a desired place).
--n.
1 something gained, achieved, etc.
2 an increase of possessions etc.; a profit, advance, or improvement.
3 the acquisition of wealth.
4 (in pl.) sums of money acquired by trade etc., emoluments, winnings.
5 an increase in amount.
6 Electronics a the factor by which power etc. is increased. b the logarithm of this.

Idiom:
gain ground see GROUND(1). gain time improve one's chances by causing or accepting delay.

Derivative:
gainable adj. gainer n. gainings n.pl.

Etymology:
OF gaigner, gaaignier to till, acquire, ult. f. Gmc

N  good, benefit, advantage, improvement, greatest good, supreme good, interest, service, behoof, behalf, weal, main chance, summum bonum, common weal, consummation devoutly to be wished, gain, boot, profit, harvest, boon, good turn, blessing, world of good, piece of good luck, piece of good fortune, nuts, prize, windfall, godsend, waif, treasure-trove, good fortune, happiness, goodness, utility, remedy, pleasure giving, commendable, useful, good, beneficial, well, aright, satisfactorily, favorably, not amis, all for the best, to one's advantage, in one's favor, in one's interest, so far so good, magnum bonum.

N  increase, augmentation, enlargement, extension, dilatation, increment, accretion, accession, development, growth, aggrandizement, aggravation, rise, ascent, exaggeration exacerbation, spread, flood tide, gain, produce, product, profit, increased, on the increase, undiminished, additional, crescendo, vires acquirit eundo.

N  skill, skillfulness, address, dexterity, dexterousness, adroitness, expertness, proficiency, competence, technical competence, craft, callidity, facility, knack, trick, sleight, mastery, mastership, excellence, panurgy, ambidexterity, ambidextrousness, sleight of hand, seamanship, airmanship, marksmanship, horsemanship, rope-dancing, accomplishment, acquirement, attainment, art, science, technicality, technology, practical knowledge, technical knowledge, knowledge of the world, world wisdom, savoir faire, tact, mother wit, discretion, finesse, craftiness, management, self-help, cleverness, talent, ability, ingenuity, capacity, parts, talents, faculty, endowment, forte, turn, gift, genius, intelligence, sharpness, readiness, invention, aptness, aptitude, turn for, capacity for, genius for, felicity, capability, curiosa felicitas, qualification, habilitation, proficient, masterpiece, coup de maitre, chef d'euvre, tour de force, good stroke, skillful, dexterous, adroit, expert, apt, handy, quick, deft, ready, gain, slick, smart, proficient, good at, up to, at home in, master of, a good hand at, au fait, thoroughbred, masterly, crack, accomplished, conversant, experienced, practiced, skilled, hackneyed, up in, well up in, in practice, in proper cue, competent, efficient, qualified, capable, fitted, fit for, up to the mark, trained, initiated, prepared, primed, finished, clever, cute, able, ingenious, felicitous, gifted, talented, endowed, inventive, shrewd, sharp, on the ball, cunning, alive to, up to snuff, not to be caught with chaff, discreet, neat-handed, fine-fingered, nimble-fingered, ambidextrous, sure- footed, cut out for, fitted for, technical, artistic, scientific, daedalian, shipshape, workman- like, business-like, statesman-like, skillfully, well, artistically, with skill, with consummate skill, secundum artem, suo Marte, to the best of one's abilities, ars celare artem, artes honorabit, celui qui veut celui-la peut, c'est une grande habilite que de savoir cacher son, expertus metuit, es bildet ein Talent sich in der Stille sich ein C, heart to conceive, the understanding to direct, or the hand to execute, if you have lemons, make lemonade.

N  acquisition, gaining, obtainment, procuration, procurement, purchase, descent, inheritance, gift, recovery, retrieval, revendication, replevin, restitution, redemption, salvage, trover, find, trouvaille, foundling, gain, thrift, money-making, money grubbing, lucre, filthy lucre, pelf, loaves and fishes, the main chance, emolument, profit, earnings, winnings, innings, pickings, net profit, avails, income, proceeds, produce, product, outcome, output, return, fruit, crop, harvest, second crop, aftermath, benefit, sweepstakes, trick, prize, pool, pot, wealth, subreption, obreption, stealing, acquiring, acquired, profitable, advantageous, gainful, remunerative, paying, lucrative, lucri causa.

VB  acquire, get, gain, win, earn, obtain, procure, gather, collect, pick, pickup, glean, find, come upon, pitch upon, light upon, scrape up, scrape together, get in, reap and carry, net, bag, sack, bring home, secure, derive, draw, get in the harvest, profit, make profit, draw profit, turn a quick profit, turn to profit, turn to account, make capital out of, make money by, obtain a return, reap the fruits of, reap an advantage, gain an advantage, turn a penny, turn an honest penny, make the pot boil, bring grist to the mill, make money, coin money, raise money, raise funds, raise the wind, fill one's pocket, treasure up, realize, clear, produce, take, get back, recover, regain, retrieve, revendicate, replevy, redeem, come by one's own, come by, come in for, receive, inherit, step into a fortune, step into the shoes of, succeed to, get hold of, get between one's finger and thumb, get into one's hand, get at, take possession, come into possession, enter into possession, be profitable, pay, answer, accrue.

capital gain, financial gain, gain ground, gain the day, gain upon, gain vigor, loop gain