Revenue, expenses, and profit
Revenue (also called income) is money the program earns: family tuition, Child Care Scholarship (CCS) payments, fees, food program reimbursements, and grants.
Expenses are the costs of running the program: payroll, rent, food, supplies, insurance, and so on.
Net income is revenue minus expenses. When it is positive, the program had a profit; when it is negative, a loss. Nonprofits use the words surplus and deficit, and call net income the change in net assets.
Gross means before something is subtracted; net means after. Gross tuition is the full tuition billed; net tuition is what remains after discounts.
A surplus is not a bad thing for a nonprofit. It is how a program builds reserves for repairs, slow enrollment months, and raises.