is  an umbrella term used to describe a number of definitions. For example, noise, in a derogatory fashion may imply the production of sound, of music or singing is unwanted and simply seen as a disturbance of the otherwise peaceful environment.
In linguistics, an allomorph is a variant form of a morpheme, that is, when a unit of meaning varies in sound without changing meaning. The term allomorph explains the comprehension of phonological variations for specific morphemes.
In phylogenetics, apomorphy and synapomorphy refer to derived characteristic of a clade. Apomorphy implies a characteristic that is different from the form of an ancestor, i.e., an innovation, of use in determining membership in a clade. Synapomorphy is a shared derived character or trait state that distinguishes a clade from other organisms. In other words, it is an apomorphy shared by members of a monophyletic group, and thus assumed to be present in their most recent common ancestor.