Most people check one number on their salary slip — what actually landed in the bank — and skip everything above it. That's fine most months, but it means a calculation error or a deduction that shouldn't be there can slide by unnoticed for a long time.
Basic salary
The fixed portion of your pay before anything else is added or subtracted. This is usually the figure used to calculate certain benefits or end-of-service payments, so it's worth knowing on its own, separate from your total package.
Allowances
Housing, transport, and sometimes food or communication allowances are added on top of basic salary. These are often untaxed or taxed differently in various countries, which is part of why employers structure pay this way rather than one flat number.
Gross pay
Basic salary plus all allowances, before any deductions. This is the number that usually gets quoted when someone talks about their "salary" in conversation, even though it's not what actually reaches their account.
Deductions
Tax, social security/pension contributions (like GOSI in Saudi Arabia), loan repayments, or insurance premiums get subtracted here. If a deduction appears that you don't recognize, this is worth asking HR about directly rather than assuming it's correct.
Net pay
Gross pay minus deductions — the actual amount deposited into your account. It's the number everyone checks, but it only makes sense in context of everything above it.