sféry

Sféry is a Czech noun in the plural form, with the singular as sféra. It denotes either the geometric notion of a sphere or, more commonly in everyday and academic language, metaphorical spheres or domains. The word is widely used in mathematics and science as well as in figurative speech to describe areas of activity, influence, or interest.

In geometry, sféra refers to the two-dimensional surface of a sphere—the set of all points at a fixed distance (the radius) from a central point. In everyday Czech, the term is often contrasted with koule, which denotes the solid ball. Outside pure geometry, sféra appears in expressions such as sociální sféra (the social sphere), ekonomická sféra (the economic sphere), or vlivové sféry (spheres of influence), highlighting its metaphorical versatility.

Etymology and word formation derive sféra from Latin sphaera, through French sphère, with Czech adaptation. The plural form sféry follows regular Czech feminine-noun patterns, shifting from the singular sféra to the nominative plural sféry in common usage.

Usage notes include its broad applicability across disciplines and its role in standard phrases describing layers, domains, or realms of concept and activity. While sféra can specify a precise geometric surface, in most contexts it signals a conceptual or organizational boundary, making it a flexible term in scientific as well as cultural discourse. See also sféra for the singular form and related terms such as sférický (adjective form in some adaptations) when discussing spherical properties.