hy·per·tro·phy 
(hī-pûrtrə-fē)
(hī-pûrtrə-fē)n. pl. hy·per·tro·phies
A nontumorous enlargement of an organ or a tissue as a result of an increase in the size rather than the number of constituent cells: muscle hypertrophy.
intr. & tr.v. hy·per·tro·phied, hy·per·tro·phy·ing, hy·per·tro·phies
To grow or cause to grow abnormally large.
hy′per·trophic (-trōfĭk, -trŏfĭk) adj.