Surgical excision of the gingiva at the level of its attachment, thus creating new marginal gingiva. This procedure is used to eliminate gingival or periodontal pockets or to provide an approach for extensive surgical interventions, and to gain access necessary to remove calculus within the pocket. (Dorland, 28th ed)

Generalized or localized diffuse fibrous overgrowth of the gingival tissue, usually transmitted as an autosomal dominant trait, but some cases are idiopathic and others produced by drugs. The enlarged gingiva is pink, firm, and has a leather-like consistency with a minutely pebbled surface and in severe cases the teeth are almost completely covered and the enlargement projects into the oral vestibule. (Dorland, 28th ed)

Abnormal enlargement or overgrowth of the gingivae brought about by enlargement of existing cells.

Excessive growth of the gingiva either by an increase in the size of the constituent cells (GINGIVAL HYPERTROPHY) or by an increase in their number (GINGIVAL HYPERPLASIA). (From Jablonski's Dictionary of Dentistry, 1992, p574)

Non-inflammatory enlargement of the gingivae produced by factors other than local irritation. It is characteristically due to an increase in the number of cells. (From Jablonski's Dictionary of Dentistry, 1992, p400)