seawater organism: a large protozoan found mainly in seawater that has a shell perforated with many small holes through which temporary cytoplasmic protrusions pseudopodia project. The calcium-containing shells of foraminifera are the main component of chalk and some limestone deposits. Order Foraminfera.
[Mid-19th century. < modern Latin Foraminifera (plural) < Latin foramen (see foramen) + -fer "bearing"]
