foraminiferan /fəˌɹamɪˈnɪfəɹən/ noun1 •An organism of the phylum Foraminifera; a foraminifer.Eocene foraminiferans are very different from Pliocene ones, and even within the Eocene there are many fine time divisions that can be recognised using foraminifera. — 2004 formsforaminiferans