Shore can be a noun meaning the part of land that meets the ocean, or a lake or river. Or it can just generally be that which is not water, or all land.
A second definition is something that prevents falling or drifting.
This second definition leads to the transitive verb (with an object) form. Usually used with the preposition up, to shore something is to use shores to support or brace it. It can also be used more generally to reinforce or support something or someone.