Entoloma sinuatum is a poisonous mushroom found across Europe and North America. Some guidebooks refer to it by its older scientific names of Entoloma lividum or Rhodophyllus sinuatus. The largest mushroom of the genus of pink-spored fungi known as Entoloma, it is also the type species. Appearing in late summer and autumn, fruit bodies are found in deciduous woodlands on clay or chalky soils, or nearby parklands, sometimes in the form of fairy rings. Solid in shape, they resemble members of the genus Tricholoma. The ivory to light grey-brown cap is up to 20 cm (7.9 in) across with a margin that is rolled inward. The sinuate gills are pale and often yellowish, becoming pink as the spores develop. The thick whitish stem has no ring.

Entoloma is a genus of fungi in the order Agaricales. Called pinkgills in English, basidiocarps are typically agaricoid, though a minority are gasteroid. All have salmon-pink basidiospores which colour the gills at maturity and are angular (polyhedral) under a microscope. The genus is large, with almost 2000 species worldwide. Most species are saprotrophic, but some are ectomycorrhizal, and a few are parasitic on other fungi. The type, Entoloma sinuatum, is one of several Entoloma species that are poisonous, typically causing mild to severe gastrointestinal illness.