0 a type of ring binder (= a piece of stiff folded material with metal rings inside for holding loose pages in position) that has three metal rings:
The classroom had filled with 36 students, each leafing silently through a fat three-ring binder.
"The records for one patient can fill a three-ring binder," she said.
He asked that documents be hole-punched to fit a three-ring binder.
