ustna

Ustna is a feminine adjective used in several South Slavic languages, including Croatian, Serbian, Bosnian, and Slovenian, meaning related to the mouth or the oral cavity. It is typically used to describe nouns that pertain to the mouth region and must agree with the gender of the noun it modifies.

In anatomical and medical terminology, ustna appears in compounds such as ustna šupljina, which translates to the oral cavity, and ustna higijena, meaning oral hygiene. The form reflects standard gender agreement in these languages, with related masculine and neuter forms used for different noun classes (for example ustni or ustno in other contexts). Beyond anatomy, ustna can appear in phrases describing mouth-related aspects of speech, digestion, or clinical procedures, again depending on language norms and regional usage.

Etymologically, the word is linked to the root referring to the mouth in the same language family, and cognate forms are found across related medical and anatomical vocabulary. Its exact spelling and inflection can vary by language standard and dialect, but the core meaning remains consistent: pertaining to the mouth.

Because ustna is an adjective rather than a standalone noun, its application is primarily within phrases that name a mouth-related feature or process. It should not be confused with unrelated terms or with forms of other roots that describe different facial parts or localities in toponymy. See also related mouth-related terms in the respective language families for broader context.