The words 'tiara' and 'diadem' can be used interchangeably as far as the actual object is concerned. The only real distinction I know of is that a diadem may be a symbol of royalty or power, while a tiara is just a jeweled thing you put on your head.
You could refer to the fine ornament on the head of a ruler as a diadem, but you wouldn't call it a tiara. You could use either word to describe the spangled object on the head of a well-dressed lady. If she's a queen or princess, and you call it a tiara, the implication is that she is not currently being an authority figure.
Interestly, objects worn by men in authority are never tiaras. So there's another distinction: a jeweled headdress worn by a man might be a diadem, which carries an implication that he's a bit exotic (or Papal). Good, manly, European dudes would never wear tiaras.
no subject
The words 'tiara' and 'diadem' can be used interchangeably as far as the actual object is concerned. The only real distinction I know of is that a diadem may be a symbol of royalty or power, while a tiara is just a jeweled thing you put on your head.
You could refer to the fine ornament on the head of a ruler as a diadem, but you wouldn't call it a tiara. You could use either word to describe the spangled object on the head of a well-dressed lady. If she's a queen or princess, and you call it a tiara, the implication is that she is not currently being an authority figure.
Interestly, objects worn by men in authority are never tiaras. So there's another distinction: a jeweled headdress worn by a man might be a diadem, which carries an implication that he's a bit exotic (or Papal). Good, manly, European dudes would never wear tiaras.