A scissor lift (jack) or mechanism is device used to extend or position a platform by mechanical means. The terms "Scissor" comes from the mechanism utilized which is configured with linked, folding supports in a crisscross 'X' pattern. The extension or displacement motion is achieved applying of force to one of the supports resulting and an elongation of the crossing pattern.
The force applied to extend the scissor mechanism may be hydraulic, pneumatic or mechanical (via a lead screw or rack and pinion system).