Option
The right — but not the obligation — to buy (a call) or sell (a put) at a set price before a set date. You pay a premium for that choice, and that asymmetry (limited loss, open-ended gain) is what makes options behave so differently from owning the asset.
Where this is taught
Definitions are the trailer. These free levels turn Option into something you play — one bite-size lesson, with worked examples, a quiz and XP.