Addendum
Pronunciation : Ad*den"dum
Part of Speech : n.; pl. Addenda.
Etymology : [L., fr. addere to add.]
Definition : Defn: A thing to be added; an appendix or addition. Addendum circle (Mech.), the circle which may be described around a circular spur wheel or gear wheel, touching the crests or tips of the teeth. Rankine.
Source : Webster's Unabridged Dictionary, 1913