O-Ring Seal
The combination of a gland and O-Ring providing a fluid tight closure. (Some designs permit minimum leakage.)
O-Ring seal in which there is relative motion between some gland parts and the O-Ring; oscillating, reciprocating or rotary motion.
O-Ring seal in which there is no relative motion between any part of the gland and the O-Ring. (Distortion from fluid pressure or swell from fluid immersion is excluded.)