I have written previously about the names of the basic types of medieval pins. In doing some further research, it seems I may have the order of things backwards.

The term fibula, plural fibulae, comes from a Latin word for pin. The leg bone was named for its resemblance to a simple pin, the precursor to the safety pin.

So any pin may be referred to as a fibula.

The penannular is also a fibula, but of a very specific type. Pen comes from the Latin paene meaning almost. Annular comes from the Latin Annulus meaning a ring, or circular. Therefore “penannular” means almost circular.

Brooch is a term used to mean any kind of pin. It comes from the Latin broochus, meaning to project, through Old French broche, a spit for roasting, and Middle English broach, a skewer or bodkin.

So a penannular brooch is still a fibula, but all fibulae are not penannular brooches.

I have several penannular brooches and other fibula available in my etsy store.