"POS" is an abbreviation for point-of-sale. On a bank statement, it is one of several labels referring to the type of bank transaction. A POS transaction is one completed with a debit card.
When you see POS under transaction type, you know that particular transaction was a purchase. If you go to a local retail shop and pay $50 for items with your debit card, for instance, your statement shows a line item for this transaction that includes POS as the type. Typically, the statement also indicates the name of the shop or place at which the transaction occurred.
The transaction type noted on the statement, such as POS, is helpful in reconciling your bank statement with your transaction ledger. It also allows you to watch for any unauthorized use of your debit card. If you see a POS transaction at a shop that you never made or authorized, you can check with your bank. Banks may offer reimbursement for unauthorized card use. A new card also is issued when the bank thinks transactions are fraudulent.