Crowns and tiaras bring visions of kings and queens. Head ornaments were worn by royalty to represent their authority and status. We often use the words tiara and crown interchangeably but there are very clear distinctions between the two. What makes a crown a crown and a tiara a tiara. The main differences are… A crown is circular whereas a tiara is semi-circular and only covers half the head. A tiara is typically worn by women whereas crowns can be worn by both men and women. A tiara is a type of crown, but a crown is not a type of tiara.