Definition
A potential sale with an expected value and close date, tracked through the stages of your pipeline.
Deal explained
Salesforce and Dynamics call deals opportunities; HubSpot and Pipedrive call them deals. Each one has an owner, an amount, a stage and an expected close date, which together drive the sales forecast.
In a mortgage CRM the equivalent is usually the loan, synced from the loan origination system; in legal software it is the matter or case.