Why is the ninth month called September?
1620s, from Late Latin suctionem (nominative suctio), noun of action from past participle stem of Latin sugere "to suck" (see suck).
A force acting on a fluid caused by difference in pressure between two regions, tending to make the fluid flow from the region of higher pressure to the region of lower pressure.
The act of reducing pressure to create such a force, as by the use of a pump or fan.
Influence; drag, pull (1940s+)