straight-teeth bevel gear
直齿伞齿轮

• sniperscope telescope
• snooper scope
• snooperscope spectrometer
• snow-shovel reflector
• soak
• soap-bubble colo(u)r
• SOA Semiconductor Optical Amplifier
• socket
• socket head
• socket wrench
• soda
• soda glass
• soda-lime glass
• soda-lime silicate glass
• soda potash glass
• sodium
• sodium carbonate
• sodium chloride
• sodium dichromate
• sodium discharge lamp
• sodium D-line
• sodium double lines
• sodium fluorescein
• sodium fluoride
• sodium hydroxide