How much you own of a property or business.
Example: Your $300,000 house has $180,000 owed to the bank: your equity is $120,000.
Example: You and your sister share equal ownership of the local bakery, so you personally have a 50% equity in it.
Example: you own 10 shares of Acme Widgets, each share is worth $80, so you have $800 equity.