Definition of "foraminiferum"

The third is a conglomerate of very minute tuff-grains, each enveloping a nucleus which proved on examination to be either a foraminiferum, a mollusk or, more rarely, a rounded particle of semi-transparent quartz.

1852, W[illiam] F. Lynch, “Reconnaissance of Route from the Bŭqâ’ at ’Ain Lijjy to Beirût”, in Official Report of the United States’ Expedition to Explore the Dead Sea and the River Jordan, Baltimore, Md.: […] John Murphy & Co., […], page 105

Mr. Hammond felt something of this practical education as he stood watching the dissolution of the grey chalk cliffs on the horizon, as the earthly kingdom, with its surging, struggling millions, its royalty and intellect, splendour and wisdom, had become but a faint outline on the narrow sea of a small quarter of a globe—itself only an orange in the universe. The whole concern merely a foraminiferum of creation.

1870, Lucius O’Brien Blake, “Un ami de Voyage”, in Rich and Rare, a Tale of Anglo-Italian Life, volume I, London: T. Cautley Newby, […], page 12

For of course, if this foraminiferum, living in a medium of fine chalk-grains, used those chalk-grains for the construction of its shell, it acquires a calcareous habitus, especially, after the diagnetic processes, it was subject to, during its fossilisation.

1932, Carel Peiter Issac van Rijsinge, Description of Some Foraminifera of a Boring Near Bunde (Dutch South-Limburg): […], page 17

Movements of intracellular particles along the lamellipodium formed by the foraminiferum Allogromia laticollaris.

1988, Alexander D. Bershadsky, Juri M. Vasiliev, “Rotational Movements of Organelles and Cytoplasm”, in Philip Siekevitz, editor, Cytoskeleton (Cellular Organelles), New York and London: Plenum Press, page 177

Foraminifera are single-cell microcrustaceans with a calcareous shell, which is a shell made of calcium carbonate. When a foraminiferum dies, its shell sinks onto the seabed.

2002, “The Neanderthals”, in Andy Klatt, transl., The Neanderthal’s Necklace: In Search of the First Thinkers, Four Walls Eight Windows, translation of El collar del neandertal by Juan Luis Arsuaga, section “Glaciation and Human Evolution in Europe”