Webster's Revised Unabridged Dictionary · 1913

Hyperplasia

Hyperplasia , noun

[New Latin, from Greek "ype`r over + {not transcribed} conformation, from {not transcribed} to mold.]

(Medicine & Biology) An increase in, or excessive growth of, the normal elements of any part.

Hyperplasia relates to the formation of new elements, hypertrophy being an increase in bulk of preexisting normal elements.