is something that is an outgrowth of something else. Depending on the subject matter, this may or may not be something abnormal and/or disfiguring.
- Excrescence (phonology) is the epenthesis of a consonant.
- In medicine and physiology, an outgrowth, especially of this skin, such as occurs in carnosity.
- Excrescence (architecture) is a feature that grows out of the main structure, particularly one added in a later period that does not harmonize with the original. "One of the worst enemies of modern Gothic architecture ... is the ``excrescence``." (John Ruskin, ``The Seven Lamps of Architecture``)