Definition of dedendum in US English:



  • The radial distance from the pitch circle of a cogwheel or worm wheel to the bottom of the tooth space or groove.

    Compare with addendum
    • ‘The base, standard pitch, addendum and dedendum circles are dashed, and the rack reference origin is highlighted.’
    • ‘The dedendum of the spur gear must be greater than the addendum of the lantern gear to prevent interference.’
    • ‘Moderate scoring shows up as a characteristic wear pattern, often in patches on the addendum, dedendum, or both.’
    • ‘You do need a hob drawing which would have the addendum equal to the dedendum of the gear you are cutting.’
    • ‘Gears have addendums and dedendums that are the amount of tooth above and below the pitch line.’


Early 20th century: from Latin, ‘thing that can be surrendered’, neuter gerundive of dedere.