(superscript⟨ᶹ⟩,IPA)[ʋ]-coloring, such as a rhotacized vowel⟨Vᶹ⟩ in some dialects of English; or a weak, fleeting or epenthetic[ʋ]. It might be used more specifically for 'secondary reduction of the lip opening accompanied by neither protrusion nor velar constriction.'[1]
(superscript⟨ᶹ⟩,VoQS)labiodentalization (a type of[ʋ]-coloring), e.g.[sᶹ],[zᶹ] and[ɹᶹ] for some individuals in English.