adjoins

Adjoins is the third-person singular present indicative form of the verb adjoin. Adjoin means to be next to or in contact with; to place in relation so that objects touch or share a boundary; or to join something to something else. The term is used widely across domains such as geography, real estate, law, and mathematics.

In geography and real estate, two parcels of land are said to adjoin if their boundaries touch or share a common boundary line. In legal contexts, the term adjoining is often used to describe neighboring properties or structures that share a boundary; disputes may arise over access, easements, or zoning with adjoined properties. In mathematics, adjoin is used to describe the operation of extending a structure by including an element or set of elements into it, commonly written as “to adjoin an element to a field.” For example, adjoining the square root of 2 to the field of rationals forms a larger field, denoted by F(a) in some texts, or by the notation F(i) when adjoining the imaginary unit.

Etymology traces to ad- “toward” + joindre “to join,” from Old French adjoindre. Related terms include adjacent, adjacency, and adjoinment; caution is needed not to confuse adjoin with adjoint or adjunction, which have distinct meanings in mathematics and logic. See also adjacent, boundary, easement, and adjoining property.