Pressure Angle: Angle between the Line of Action and a line perpendicular to the Line of Centers.

Pitch Point: The point of tangency of the pitch circles of two meshing gears, where the Line of Centers crosses the pitch circles.

Diametral pitch: Ratio of the number of teeth to the of pitch circle diameter.

Pitch Circle: The circle, the radius of which is equal to the distance from the center of the gear to the pitch point.

Module: Ratio of Pitch Diameter to the number of teeth.Line of Action: That line along which the point of contact between gear teeth travels, between the first point of contact and the last.Pinion: The smaller of the two meshing gears is called pinion.Wheel:Larger of the two meshing gears is called wheel.

Flank: The working surface of a gear tooth, located between the pitch diameter and the bottom of the teeth.Face Width: The width of the tooth measured parallel to the gear axis.Face: The working surface of a gear tooth, located between the pitch diameter and the top of the tooth.Diametral Pitch: Teeth per mm of diameter.Dedendum: The radial distance between the bottom of the tooth to pitch circle.Contact Ratio: The ratio of the length of the Arc of Action to the Circular Pitch.Clearance: The distance between the top of a tooth and the bottom of the space into which it fits on the meshing gear.Circular Thickness: The thickness of the tooth measured along an arc following the Pitch Circle.Circular Pitch: Millimeter of Pitch Circle circumference per tooth.Chordal Thickness: The thickness of the tooth measured along a chord passing through the points where the Pitch Circle crosses the tooth profile.Chordal Addendum: The distance between a chord, passing through the points where the Pitch Circle crosses the tooth profile, and the tooth top.Center Distance: The distance between centers of two gears.Base Circle: The circle from which is generated the involute curve upon which the tooth profile is based.Arc of Recession: That arc of the Pitch Circle between the Pitch Point and the last point of.Arc of Approach: Is the arc of the Pitch Circle between the first point of contact of the gear.Arc of Action: Is the arc of the Pitch Circle between the beginning and the end of the.

Addendum:The radial distance between the Pitch Circle and the top of the teeth.

The circle of gear order of the stick