On the homepage, there's a donut chart that shows:

This article breaks down what opportunities are and how they can help your business.

A new opportunity is created whenever a contact enters a pipeline.

It essentially means "an opportunity to close a sale."

A won opportunity is created whenever a contact exits a pipeline successfully (i.e. moved to the end of the pipeline).

This corresponds to successfully closing a sale.

A lost opportunity is created whenever a contact exits a pipeline unsuccessfully (i.e. dropped from the pipeline).

This corresponds to losing a sale.

By tracking wins, losses, and total opportunities, you unlock the ability to see exactly which points in your sales process need to be improved.

You can navigate to Contacts → Analytics to see a detailed breakdown of your pipeline performance.