attachedadj.1. fastened together.()2. being joined in close association; -- of people or organizations.()3. fastened onto another object; -- of objects smaller than the main object.()4. (Architecture) connected by a common wall or passageway; -- used of buildings.()5. (Biology) permanently attached to a substrate; not free to move about.()6. associated in an exclusive sexual relationship; -- opposite of unattached.()