1.
stapler
A device for fastening papers together with metal staples.
ホッチキス is the common Japanese word for "stapler." An example of a brand name becoming a generic term.
Etymology
Named after the E.H. Hotchkiss company that sold staplers in Japan. Similar to how "Xerox" means "photocopy" in some languages.
Common expressions
Alternative
ステープラー is the technical/formal term, but ホッチキス is far more common in everyday speech.