triple point

1. The unique temperature and pressure at which the solid, liquid and gas phases of a substance are all in equilibrium.

   Tripelpunkt

   тро́йная то́чкаtrójnaja tóčka

2. A point where the incident shock wave, the reflected shock wave, the Mach stem, and one slipstream meet.

3. A point where a curve or surface intersects itself along three arcs.

4. The intersection of an occluded front, cold front, and warm front.

5. The point where two boundaries, such as a dry line, outflow boundary, or cold front, intersect.

6. A point where three plates intersect.

regular