Scissors

Scissors are a hand-operated cutting instrument with two blades joined at a pivot and handles that move the blades against one another to cut material.

Lever: A rigid bar that pivots around a fulcrum to transmit or multiply force. Each handle and blade acts as a lever around the central pivot.
Blade: A flat or shaped part of a tool with an edge designed to cut or scrape. Each scissor half includes a blade whose edge meets its partner during cutting.
Paper scissors: Scissors designed for cutting paper and similar lightweight sheet materials. Their general-purpose blades suit the material named in the instrument's basic use.
Knife: A tool with a sharp blade used for cutting, slicing, or stabbing. A knife usually cuts with one edge against a surface rather than two crossing blades.
Fulcrum: A fixed point around which a lever turns. The screw or rivet between the blades serves as the fulcrum.
Cutting edge: The sharpened boundary of a tool that penetrates or separates material. The two cutting edges perform the separation as the blades pass one another.
Fabric scissors: Scissors designed to cut woven or knitted textiles. Long, sharp blades help cut cloth without shifting or snagging it.
Shears: A cutting tool with two pivoted blades, typically larger or heavier than scissors. Shears share the basic mechanism but are built for larger-scale or tougher cutting.
Shear force: A force that acts parallel to a surface and causes adjacent parts to slide past one another. Crossing blades cut by applying opposing shear forces to material.
Pivot joint: A connection that allows joined parts to rotate around a fixed axis. A pivot joint lets the blades rotate while remaining aligned.

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