invert

1. An inverted arch (as in a sewer).
2. The base of a tunnel on which the road or railway may be laid and used when construction is through unstable ground. It may be flat or form a continuous curve with the tunnel arch.
3. The lowest point inside a pipe at a certain point.
4. An elevation of a pipe at a certain point along the pipe.
5. A skateboarding and snowboarding trick where the skater grabs the board and plants a hand on the coping so as to balance upside-down on the lip of a ramp.
6. Of a person, assumed to be transgender, in terms of transvestigation.
7. A stamp accidentally printed upside-down.

Plural inverts