iddingsiteEnglishOxford New American Dictionaryiddingsite /ˈidiNGˌzīt, ˈɪdɪŋˌzaɪt / ▸ noun a brownish mineral deposit consisting of a mixture of silicates, formed by alteration of olivine. – ORIGIN late 19th century : from the name of Joseph P. Iddings (1857–1920), American geologist, + -ite1.