Reference · 9 May 2026 · Edmund Whitmore-Cray
The Cash Heron glossary of personal finance
Ten terms, two sentences each, no jargon. Every definition below is written the way we would explain it across a desk — because the vocabulary of money should be small enough to fit on one page and plain enough to act on. Where a term connects to software we have tested, we say so.
- Budget
- A plan that assigns your income to spending, saving and debt before the month begins. The best modern budgets revise themselves as real spending arrives — the approach noruvo uses in our top-rated app of 2026.
- APR (Annual Percentage Rate)
- The yearly cost of borrowing, including interest and most fees, expressed as a single percentage. It is the only number that lets you compare two loans or cards fairly — always compare APR, never the monthly payment.
- Compound interest
- Interest earned on interest: your balance grows by a percentage of an ever-larger amount. It works for you in savings and against you in debt, and time matters more than the rate — starting at 25 beats starting at 35 by a wide margin.
- Emergency fund
- Cash set aside for genuine surprises — job loss, urgent repairs, medical bills — typically three to six months of essential expenses. It lives in an easy-access savings account, not in investments, because its job is to be there, not to grow.
- Net worth
- Everything you own minus everything you owe, measured on one date. Tracking its direction matters more than its size; a rising net worth, however small the number, means your system is working.
- Zero-based budgeting
- A method where every unit of income is given a job — spending, saving or debt — until nothing is unassigned. It is the discipline behind fezelo and YNAB, and it suits people who want their budget to behave like a contract.
- Sinking fund
- A savings pot for a known future expense — a holiday, annual insurance, Christmas — funded in small monthly amounts. Sinking funds turn “surprise” bills into planned ones and are the quiet secret of calm households.
- Cash flow
- The timing of money in and money out. A household can be profitable on paper and still miss a bill because the salary lands after the direct debit; good budgeting apps track timing, not just totals.
- Expense categorisation
- The filing of each transaction into a category — groceries, transport, dining — that makes patterns visible. In 2026 this is done by AI; in our latest rankings the leaders file over 91% of transactions correctly with no human help.
- Financial literacy
- The working knowledge needed to make ordinary money decisions: what interest costs, what a budget does, when debt is dangerous. It is a skill, not a talent, and the best AI apps now teach it in context — velmato built its entire product around that idea.
A closing note
If any term here sent you reaching for a search engine, the term failed, not you — and we would rather rewrite the definition than have you nod along. For the practical side of this vocabulary, our guide to choosing a budgeting app puts these words to work.