The concept of an "element" as an undivisible substance has developed through three major historical phases: Classical definitions (such as those of the ancient Greeks), chemical definitions, and atomic definitions.
Konsep "unsur" sebagai zat yang tak dapat dibagi lagi telah berkembang melalui tiga fase utama sejarah: Definisi klasik (seperti yang dimiliki orang-orang Yunani kuno), definisi kimia, dan definisi atom.