accession

noun | \ ik-ˈse-shən, ak- \ | ac·ces·sion

1. : increase by something added; specifically : the mode of acquiring property by which the owner of property (as a building, land, or cattle) becomes the owner of an addition by growth, improvement, increase, or labor : the mode of acquiring property by which the owner of property (as a building, land, or cattle) becomes the owner of an addition by growth, improvement, increase, or labor

2. : the act of assenting or agreeing