dilatante

Dilatante is an adjective used in Spanish and Portuguese to denote something that causes widening, expansion, or dilation. It derives from Latin dilatans, the present participle of dilatare “to widen.” The term appears across several technical domains with a similar sense of dilation, and English-language equivalents include dilatant or vasodilatant where appropriate.

In medicine and pharmacology, dilatante describes substances or actions that widen a passage or vessel. A vasodilatante drug causes vasodilation, and ophthalmologic contexts may refer to dilatante agents that dilate the pupil.

In geotechnical engineering and soil science, dilatante soils expand in volume when subjected to shear, a phenomenon known as dilatancy. This behavior affects shear strength, drainage, and compaction in soils and granular materials.

In rheology and materials science, dilatante or dilatant materials exhibit positive dilatancy: their volume increases with increasing shear rate. Dense suspensions and certain non-Newtonian fluids can show this behavior, transitioning from fluid-like to solid-like under rapid agitation or impact.

The term is most common in Spanish- and Portuguese-language technical literature, with English-language usage often rendered as dilatant or vasodilatant.