In a sale
Equity value is enterprise value once the debt is repaid and the cash in the business is settled: what is left for the owners, before fees, the timing of the payments, and tax. It is closer to what the founder receives than the headline. Reading an offer from enterprise value down to equity value, and then to net proceeds, is how offers are compared on take-home.
Where it comes up
The Go-To-Market Analysis (GTMA) builds the file a buyer would build on your business, before a buyer does.