Definitions:

1. A mechanism consisting of a circular gear (the pinion) engaging with a linear gear (the rack), that as the pinion rotates it moves the rack in a straight line. NOUN
   • Engineers chose a rack and pinion system to achieve accurate linear motion in the robotic arm.
2. Refers to a mechanical system that converts rotational motion into linear motion, commonly used in steering systems and machinery. NOUN
   • The car's rack and pinion steering provides precise control and responsiveness.

Synonyms:

• gear
• linear actuator
• mechanical transmission
• steering rack