penknife

UK: /ˈpɛnnaɪf/ US: /ˈpɛnˌnaɪf/ ,(pen′nīf′)

Inflections of 'penknife' (n): npl: penknives

WordReference Random House Learner's Dictionary of American English © 2025

pen•knife /ˈpɛnˌnaɪf/   n. [countable] , pl. -knives. 

1. a small pocketknife.

WordReference Random House Unabridged Dictionary of American English © 2025

pen•knife  (pen′nīf′), n., pl. -knives. 

1. a small pocketknife, formerly one used for making and sharpening quill pens.

• 1400–50; late Middle English; see pen¹, knife

Collins Concise English Dictionary © HarperCollins Publishers::

penknife / ˈpɛnˌnaɪf/ noun ( -knives)

1. a small knife with one or more blades that fold into the handle; pocketknife

Etymology: 15th Century: so called because it was originally used for making and repairing quill pens