stock power

A power of attorney that allows the current owner of a registered security to transfer ownership to another party.

Investopedia Says:
The party to whom ownership is being transferred can be a bank, brokerage firm, or another investor. Stock power may also be granted if the stock is pledged as collateral for a loan.

Power of attorney form transferring ownership of a Registered Security from the owner to another party. A separate piece of paper from the Certificate, it is attached to the latter when the security is sold or pledged to a brokerage firm, bank, or other lender as loan Collateral. Technically, the stock power gives the owner's permission to another party (the Transfer Agent) to transfer ownership of the certificate to a third party. Also called stock/bond power.

The noun has one meaning:

Meaning #1: a power of attorney document to transfer ownership of a registered security from the owner to another party