astroid /asˈtroid/ (mathematics)

A hypocycloid with four cusps

• pencil-cases
• pencil-cedar
• pencil-cedars
• pencil-compass
• pencil-compasses
• penciling
• pencil-lead
• pencil-leads
• pencilled
• penciller
• pencillers
• pencilling
• pencillings
• pencil moustache
• pencil moustaches
• pencil-ore
• pencil-pusher
• pencils
• pencil-sharpener
• pencil-sharpeners
• pencil-sketch
• pencil-sketches
• pencil skirt
• pencil skirts
• pencil-stone