chemical element, element - any of the more than 100 known substances (of which 92 occur naturally) that cannot be separated into simpler substances and that singly or in combination constitute all matter

apatite - a common complex mineral consisting of calcium fluoride phosphate or calcium chloride phosphate; a source of phosphorus

Latin alphabet, Roman alphabet - the alphabet evolved by the ancient Romans which serves for writing most of the languages of western Europe

alphabetic character, letter of the alphabet, letter - the conventional characters of the alphabet used to represent speech; "his grandmother taught him his letters"