perforation
(1)胶片孔，孔眼
(2)穿孔，凿孔

• sewage
• sexadesimal system
• sextant
• sextet
• Seya concave-gratin monochromator
• shackle
• shade
• shaded area
• shading
• shadow
• shadow angle
• shadow area
• shadow band
• shadow-casting
• shadow cone
• shadoweffect
• shadowgraph
• shadow image
• shadowing method
• shadow mask
• shadow-mask screen
• shadow microscope
• shadow-Moire test
• shadow photometer
• shadow scattering