Adjacent means “next to” or “very near,” often sharing a side, wall, edge, or boundary with something else.

Core meaning

  • Adjacent is an adjective that describes two things that are side by side or close to each other.
  • They may simply be nearby, or they may actually touch or share a border, wall, or endpoint.

Put simply: if A is adjacent to B, A is right next to B.

Everyday examples

  • Two hotel rooms with doors next to each other are adjacent rooms.
  • Your next‑door neighbor’s flat or house is adjacent to yours.
  • A conference room next to the main hall is adjacent to the hall.

In all of these, you can go from one to the other with almost no distance in between.

In math and technical contexts

  • Geometry: Adjacent angles share a common vertex and a common side, with no gap or overlap between them.
  • Polygons: Adjacent sides are two sides that meet at the same vertex (for example, sides PQ and QR in triangle PQR).
  • Technical/official language: Laws, planning documents, and reports often say “adjacent property,” “adjacent buildings,” or “adjacent suburbs” for areas that share a border or are immediately nearby.

Synonyms and nuance

Common near-synonyms include neighboring , nearby , bordering , and adjoining.

  • “Adjacent” is a bit more formal and is especially common in math, law, and technical writing.
  • “Adjoining” usually emphasizes that things are connected (for example, two hotel rooms with an internal door), while “adjacent” can be either just next to or actually touching.

TL;DR: Adjacent means “right next to” or “side by side,” often with a shared border, wall, or edge.