Sileää

Sileä is a Finnish adjective meaning smooth, even, or sleek. It describes a surface or texture that lacks roughness or irregularities, for example sileä pinta (a smooth surface), sileä iho (smooth skin), or sileä tie (a smooth road). The term can also describe non-physical qualities, such as a fluent or uncluttered delivery, though this usage is less common in everyday speech.

Grammatical notes: Sileä declines like other Finnish adjectives. The positive form is sileä; the comparative form is sileämpi; the superlative form is silein. Finnish adjectives agree with the noun they modify in number and case, so forms change accordingly in sentences.

In mathematics and related fields, sileä is used to translate the English word smooth. A sileä funktio is a function that is differentiable to the required degree, typically with continuous derivatives of all orders. The concept also appears as sileä pinta in geometry, referring to surfaces without corners or edges in idealized contexts.

Etymology and usage: The word sileä is of Finnish origin and is contrasted with karkea, meaning rough. Related expressions include tasainen (even, flat) and kiiltävä (shiny), though kiiltävä emphasizes shine rather than texture.

See also: texture, surface roughness, smooth function, Finnish grammar.