Plain-English definitions of the paper trading and stock market terms you'll actually run into, no jargon, a worked example for each, and a way to practice it for free. JagSim is a free simulator with $100k in virtual cash and real 15-minute delayed data. Pick a term, then go try it.
An order to buy or sell right now at the best available price.
An order that only fills at your chosen price or better.
An order that sells automatically if the price drops to a level you set.
Betting a price will fall by borrowing shares to sell now and buy back later.
How much you can spend on new positions right now.
Deciding how much money to put into a single trade.
Everything you hold: your cash plus all your open positions.
How much money a trade or account has made or lost.
Practicing trades with virtual money instead of real cash.
Opening and closing trades within the same day.
How much and how fast a price swings up and down.
The gap between the highest buy price and lowest sell price.
Last updated: July 2026 · Educational only. Not investment advice. JagSim is a simulator, not a broker.