They hope to make big 'gains' in Congress in the coming election. [=they hope that many more members of their party will be elected to Congress]
Her hard work 'gained' her their respect. [=she has gained their respect through hard work; they respect her now because of her hard work]
a stock that was one of the year's biggest 'gainers' [=one of the stocks that increased the most in value]
(..) causing an obstruction! You don't disperse, you're gonna be arrested. I promise you! Sheriff Clark, we're trying to gain access to the registration office. Which is our legal right. There's too many of you. And you know damn well there is! Now, y'all just gonna have (..)2014 Selma