401(k)
A tax-advantaged, employer-sponsored retirement account.
A 401(k) is a retirement savings account offered through an employer, letting you invest a portion of each paycheck before (or, for a Roth 401(k), after) taxes. Contributions grow tax-advantaged until retirement. Many employers match part of your contributions — often called free money (though employer contributions may vest over a few years) — which is why capturing the full match is usually the highest-return move available to you.