(Zool.) A brachiopod shell of the genus Orthis, and allied genera, of the family Orthidæ.
Orthid
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Orthid
[′ȯr·thəd] (geology) A suborder of the soil order Aridisol, mostly well drained, gray or brownish-gray with little change from top to bottom of the soil profile; occupies younger, but not the youngest, land surfaces in deserts.