v. 1
To acquire possession of.
Looks like you’ve gained a new friend.
n. 1
The act of gaining; acquisition.
People are more willing to take a risk to avoid a loss than to make a gain.

Related words

Word family: gainer gainless gainword gainworthy gainful
Phrases: gain ground gain over gain steam gain weight gain momentum gain on gain one's spurs gain the wind

Forms

Plural: gains → increases, accesses, acquisitions, additions…
Past participle: gained
e.g. gained → attained, obtained, achieved, earnt…

Choose the right word

Gain or Win?

Win denotes contest, with a suggestion of chance or hazard; in popular language, a person is often said to win a lawsuit, or to win in a suit at law, but in legal phrase he is said to gain his suit, case, or cause.

J. C. Fernald, English Synonyms and Antonyms (1914)

Example sentences

achieve My mission is to help people achieve their dreams.
earn Tom doesn't earn enough money to support a family.
obtain I am able to obtain a registration form for free.
attain To attain his goal, Tom moved the heaven and earth.
benefit Advances in science don't always benefit humanity.
gather You must gather your party before venturing forth.

Popularity over time

Word	1850 → 2019	Trend
gain		steady
achieve		steady
earn		steady
obtain		falling
attain		falling
benefit		steady

Use in printed books, per decade from 1850 to 2019.

By length

3 letters: win¹, hit¹, net¹
4 letters: have¹, make¹, good¹, take¹, find¹, fast¹, edge¹, earn¹, reap¹
5 letters: store¹, reach¹, prize¹, prise, lucre
6 letters: access², income², profit², obtain², gather², attain², garner², derive²
7 letters: realize³, improve², benefit³, achieve², realise³, acquire³, procure²
8 letters: increase², addition³, earnings², blessing²
9 letters: advantage³, increment³, accretion³, crescendo³
11 letters: acquisition⁴
12 letters: accumulation⁵
13 letters: amplification⁵

The small number after each word is its number of syllables (access² = 2 syllables).