- solar heat
- solar neutrino
- solar spectrum
- solarization
- sound intensity
- sound locator
- sound spectrograph
- sound-absorbing
- source range
- soxhlet extractor
- spacing
- spare bulb
- spark discharge
- spectra
- spectral distribution
- spectral emissivity
- spectral pitch
- spectral range
- spectral sequence
- spectral term
- spectrograph
- spectroheliogram
- spectrophotography
- spectroradiometer
- spectrum
- speech audiometer
- speed direction
- sound frequency
- soundness
- source reactor
- spalling force
- span
- spark
- spark counter
- spark spectrum
- spatial quantization
- specific
- spectral
- spectrogram
- spectrohelioscope
- spectrometric analysis
- spectrophotometer
- speech audiometry
- specific activity
- specific energy
- specific entropy
- specific ionization
- specific loudness
- specific rotation
- spectral band
- spectral factorization
- spectral luminance
- spectral reflectance
- spectral transmittance
- spectroheliograph
- spectrometer
- spectrometry
- spectrophotometry
- spectroscope
- spectroscopic method
- spectroscopy
- spectrum analysis
- spectrum level
- speech audiogram
- spherical lens
- sphygomanometer
- spin wave
- spinning bodies
- spider lines
- spinsthariscope
- spiral track
- spondee
- spot
- spotting plate
- spray drag
- spring brake
- sprocket hole
- square potential
- square-law
- spintemperature
- spinthariscope
- spintronics
- spiral turbulence
- split
- spontaneous activity
- sports finder
- stability
- stable
- stage relation
- stagnant space
- stagnation pressure
- standard lens
- standard meter
- standard sound
- standard source
- spoiler
- spontaneous decay
- spontaneous excitation
- spontaneous transitions
- spooling