megalonychosis

macronychia

A condition in which the finger- and/or toenails are larger than normal, usually wider than they are long, due to shortening of the bone of the distal phalanx.
 
Aetiology
Idiopathic, Proteus syndrome, Rubinstein Taybi syndrome.
Segen's Medical Dictionary. © 2012 Farlex, Inc. All rights reserved.

megalonychosis

(mĕg′ă-lō″nĭ-kō′sĭs) [″ + onyx, nail]
Hypertrophy of the nails.
Medical Dictionary, © 2009 Farlex and Partners