What is the meaning of Excrescence?

Something, usually abnormal, which grows out of something else.

A disfiguring or unwanted mark or adjunct.

The epenthesis of a consonant, e.g., warmth as [ˈwɔrmpθ] (adding a [p] between [m] and [θ]), or -t (Etymology 2).

Source: wiktionary.org