- selective interrogation
- self-guidance
- self-interference
- self-location
- self-tracking
- semantic check
- semi-conductor
- semiautomatic system
- semiconductor chip
- semiconductor crystal
- semicustom circuit
- selection priority
- selection sort
- selective calling
- selective circuit
- selective feedback
- self-assumed
- self-identification
- self-test
- semi-angle
- semiconductor fabrication
- sender
- sense antenna
- sense byte
- sense remotely
- sense signal
- sensing antenna
- sensing station
- sensitive emulsion
- sensitivity test
- sensor
- sensor system
- separated links
- sequence number
- sequence numbering
- sequence running
- sequenced frame
- sequential decoding
- sequential hunting
- sequential operation
- serial access
- serial carry
- Serial correlation
- serial interface
- serial port
- serial subtracter
- serial transfer
- segmented motor
- seize
- seizure
- selecting region
- selection amplifier
- selection panel
- selection signal
- self-checking
- self-determination
- self-existent
- self-expression
- Self-financing
- self-tracing
- semi-double
- semiconductor amplifier
- semiconductor component
- semiconductor crosspoint
- semiconductor junction
- semiconductor layer
- semiconductor material
- semiconductor substrate
- semitone
- sender group
- sending lever
- senior officer
- sense data
- sensor pod
- sensor signal
- separation filter
- separator
- separator string
- septum
- sequence controller
- sequence field
- sequence key
- series network
- server
- service 800
- service abbreviation
- service arc
- service bay
- service break
- service circuit
- service communication
- service contour
- service differential
- service disruption
- service duct
- service layer
- service oscillator
- service probability
- service provider
- service sector