- SAM
- scaphocerite
- sculpturation
- segment
- SMF
- somite
- Southeast Atlantic
- Southeast Pacific
- Southern Ocean
- Southwest Atlantic
- Southwest Pacific
- spermatophore
- squame
- stalk
- sternite
- sternum
- stridulating organ
- stylet
- subchela
- subdorsal carina
- submarginal posterior groove of the carapace
- supraorbital spine
- swimmeret