To bind or fasten something securely with a rope, string, or cord. She tied up the package with a piece of twine.
To occupy or engage someone or something, preventing them from being available for other tasks. The meeting tied up all the managers for the entire afternoon.
To secure a boat to a dock or mooring. They tied up the boat at the marina before heading into town.
To invest or commit resources, such as money, in a way that they are not easily accessible. He tied up his savings in long-term investments.