s Sample standard deviation

s Second / Seconde

S Siemens (conductivity)

Sat Saturday / Samedi

sbe Standard brick equivalent (Harmonized System - See HS)

SE Standard Error

sec secant (trigonometric function)

Sem Semaine

Sept September / Septembre

September Septembre
Du lat. september, de septem, sept, parce que, dans l'ancienne année romaine commençant au mois de mars, septembre était le septième mois

Sextillion 10³⁶

SI International System of Units / Système International d'Unités / Sistema Internacional de Unidades(standard metric units replacing MKS and MKSA systems) - See NIST SI

Si kg Silicon content in kilograms (Harmonized System - See HS)

SMY Solar Maximum Year

SNR Signal to Noise Ratio

Sound See Velocity of sound

Speed of light (2.997 924 58 x 10⁸ ms^-1)

Sq Square / Carré

sq. cm Square centimeter / Centimètre carré

sq. ft Square foot

sq. in Square inch

sq. km Square kilometer

sq. yd Square yard

sr Steradian / Stéradian

St Stere / Stère (1 stere = 1 cubic meter)

St Stokes

ST Short Ton (1 ST = 907.2 kilograms = 0.9072 metric ton)

std ft³ Standard cubic foot

stp Standard Temperature and Pression standard temperature and pressure (0 and 1 atm)

Sun Sunday / Dimanche

Sv Sievert

Sw ShortWave

SY Seasonal Year