- smoke flue
- snatch off
- snow adherence
- snow icing
- snow nozzle
- snow-frozen
- sodium chloride
- softener
- soil freezing
- solar
- solar activity
- solar atmosphere
- solar flare
- solar generator
- solar heater
- solar refrigeration
- solar time
- solderless
- solderless contact
- sound locator
- sound production
- sound reflection
- sound take
- sound-ranging
- sounder
- sounding line
- soundless
- south pole
- space division
- space factor
- space shuttle
- space thermostat
- space wave
- spacing
- spark chamber
- spark coil
- spark ignition
- spark plate
- spark suppressor
- spark-meter
- sparking ball
- spatial arrangement
- speckle interferometer
- speckle pattern
- specklegram
- spectral absorption
- Spectral analysis
- spectral artifact
- spectral distribution
- spectral emissivity
- spectral filter
- spectral line
- spectrocomparator
- spectrometric
- spectrometric method
- spectrophotometric
- spectroscopic
- spectroscopic technique
- spectrum line
- spectrum selectivity
- speculum metal
- speech sample
- speech sound
- speed control
- speed regulator
- speedometer
- spent steam
- sphere frustum
- sound field
- sound frequency
- sound rays
- sound shadow
- sound transducer
- sound transmission
- sounding
- source current
- space probe
- space requirements
- space simulation
- space state
- space station
- space-exploration
- space-time
- spacecraft
- spaceship
- spaghetti
- span
- spanner
- spar
- spark capacitor
- spark counter
- spark killer
- spark voltage
- sparking potential
- spatial structure
- SPDT
- special effects
- special function
- specific charge
- specific enthalpy