rastrum (RAS-trum) - n., a pen for drawing the five lines of a musical stave simultaneously.
Plural is rastra. Here's a traditional fountain-pen version:

Thanks, WikiMedia!
Modern ones are typically five ball-point or roller-ball pens. I've had music teachers that had five-chalksticks versions, though with chalkboards on their way out, I assume they now use five-whiteboard-markers instead. The word in Latin originally meant a rake.
---L.
Plural is rastra. Here's a traditional fountain-pen version:

Thanks, WikiMedia!
Modern ones are typically five ball-point or roller-ball pens. I've had music teachers that had five-chalksticks versions, though with chalkboards on their way out, I assume they now use five-whiteboard-markers instead. The word in Latin originally meant a rake.
---L.