Contact

n.
  1. A close union or junction of bodies; a touching or meeting.
  2. (Geom.) The property of two curves, or surfaces, which meet, and at the point of meeting have a common direction.
  3. (Mining) The plane between two adjacent bodies of dissimilar rock.
  4. (Electricity) A metallic conducting component of an electrical device connected to a circuit within and so situated that it may form a conducting pathway to an external power source or device when contacted by another conductor; as, the contact on a standard light bulb has the shape of a screw for easy insertion into the socket.
  5. A person who serves to commmunicate information to or from one group to another, whether formally or informally; as, a good Washington reporter has contacts in the White House.
    6. Contact level ,
    a delicate level so pivoted as to tilt when two parts of a measuring apparatus come into contact with each other; -- used in precise determinations of lengths and in the accurate graduation of instruments.