mitre

1. A covering for the head, worn on solemn occasions by church dignitaries, which has been made in many reincarnations, most recently as a tall cap with two points or peaks.
2. The surface forming the bevelled end or edge of a piece where a miter joint is made; also, a joint formed or a junction affected by two bevelled ends or edges; a mitral joint.
3. A 13th-century coin minted in Europe which circulated in Ireland as a debased counterfeit sterling penny, outlawed under Edward I.
4. A cap or cowl for a chimney or ventilation pipe.
5. A gusset in sewing, etc.
6. A mitre shell

Plural mitres