A sponge with a soft body that covers a hard, often massive skeleton made of calcium carbonate, either aragonite or calcite.

trichromatic (involving three colours) / (cytology, of a stain) Staining three different tissues three different colours.

present participle of gangstalk

A strong shoe for heavy-duty use, a boot. / (US) Any kind of shoe. / (military slang) United States Navy ankle length work shoes, distinct from dress shoes or combat boots. / A peasant or yokel.