Envelope budgeting borrows vocabulary from YNAB, Actual, and traditional household finance. Here is what each term means in Project Budget.

Ready to Assign: Money you have received but not yet given a job. It comes from inflow transactions you marked as ready-to-assign and any unassigned balance carrying over from prior months.
Assigned: The dollar amount you have committed to a category for the current month. Assigning does not move money between accounts — it just labels intent.
Activity: The sum of spending in a category during the current month. Inflow transactions to a category show as positive activity.
Available: What is left in a category after subtracting activity from assigned and adding any carry-in from the previous month.
Carry-over: The available balance in a category at month-end rolls into the same category's starting balance next month. Negative available in an on-budget category does not roll; it reduces next month's Ready to Assign.
On-budget account: An account whose balance contributes to Ready to Assign. Checking, savings, cash, and credit cards are typically on-budget.
Tracking account: An account whose balance counts toward net worth but not toward Ready to Assign. Investments, home value, vehicles, mortgages, and loans are tracking accounts.
Reconciliation: The process of matching your Project Budget account balance to the balance shown by the bank or card issuer. Reconciled transactions are locked to prevent edits.
Split transaction: A single transaction whose amount is divided across two or more categories — for example, a grocery store run that included household supplies.
Transfer: A movement of money between two of your own accounts. Transfers are entered once and Project Budget creates the matching entry in the other account.
Goal: A target you set on a category — either a fixed monthly amount, a balance to reach by a date, a refill amount each month, or a top-up that adds on top of last month's rollover.
Credit card payment category: Created automatically with every credit card account. As you spend against the card, an equal amount moves from the spent category into this one — so the cash is set aside to pay the bill.