sing - snap
- single action
- single seal
- single stage pump with overhung rotor type and centerline support type of pump casing
- single stage pump with overhung rotor type and foot support type of pump casing
- SIO
- siphon pipe
- SIS
- site acceptance testing
- skew compensation
- skip
- SL
- sleeper support
- sleeve pipe
- sliding door
- sliding plate
- slime control agent injection
- slip
- SLO
- slop
- slop oil
