brokerage
A brokerage is a company that lets you open accounts and buy or sell investments like stocks, and many people use one to hold their IRA.
Where it is explained in full
When size changes the answer: ten dollars, ten thousand, and a hundred million are not the same money. Arithmetic scales in a straight line. The world does not. Past certain sizes, insurance runs out, prices move against you, rules change, and the cheap thing becomes expensive or the expensive thing becomes cheap. This page names the lines.
An account is not an investment. The single most useful thing to understand about money, and the one most people were never told. The box and the thing inside the box are two different choices.
Workplace plans: the 401(k), the 403(b), and the TSP, from the first paycheck to the last. Everything a person needs to open one, fill it, hold the right things in it, avoid the traps, and carry it with them when they leave. Long on purpose, so that one page is enough.
Funds: what you actually own when you buy one. Both kinds are baskets. The differences are in how you buy them, how they are priced, how they handle taxes, and what it costs to hold them for decades.
A definition says what a thing is; it never says whether it fits you. The guides explain how it works and name the professional who confirms it for a particular person. The No Advice Disclosure.
Ask about brokerage
A model reads this page and answers from it. It will say when the answer is not on the page. Education, not personalized advice.