A purchase requisition is an internal document: somebody asking permission to buy something before any supplier has been contacted. It is routinely confused with a purchase order, and the difference is not pedantry. The two are approved by different people, for different reasons, at different moments, and getting the order of those moments wrong removes the control.
What the word means in practice
A request, raised by whoever needs the thing, stating what, roughly how much, which budget, when and why. It is internal, it commits nobody outside the organisation, and it can be declined at no cost. That last property is the whole reason it exists as a separate step.
How it differs from a purchase order
The requisition asks permission; the order makes the commitment. The requisition is approved by a budget holder deciding whether to spend; the order is issued by purchasing having chosen a supplier and agreed a price. An approved requisition becomes an order, and the link between them should carry the approval forward.
Why the sequence matters
Approving after an order has gone out means approving a commitment that already exists, which is a review rather than a decision. Approvers in that position learn their signature is a formality and stop reading carefully. Keeping the approval at the requisition keeps it a real choice, which is what makes it worth anybody's attention.
Questions people ask about purchase requisition meaning
Is a requisition legally binding?
No. It is internal. The commitment to a supplier is made by the purchase order or a contract.
Who raises one?
Whoever needs the goods or service, usually somebody outside finance, which is why the form must be short.
Do small purchases need one?
Most organisations set a threshold. Setting it deliberately beats leaving people to guess, which produces inconsistent practice.