AL'LANITE, noun A mineral named from Mr. Allan, of Edinburg, who first recognized it as a distinct species. It is massive, of a brownish black color, and conchoidal fracture. A siliceous oxyd of cerium. ALLANTOIS'or ALLANTOID', noun [Gr. a sausage, and form.] A thin membrane, situated between the chorion and amnios in quadrupeds, and forming one of the membranes which invest the fetus in those animals.
Source: Webster's 1828 American Dictionary ↗ · public-domain · returned verbatim, no AI