sharpen

UK: /ˈʃɑː^rpən/ US: /ˈʃɑrpən/ ,(shär′pən)

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

sharp•en /ˈʃɑrpən/   v. 

1. to make or become sharp or sharper: [~ + object]
   to sharpen a knife.
   [no object]
   This knife won't sharpen.

sharp•en•er, n. 

[countable] a pencil sharpener.

WordReference Random House Unabridged Dictionary of American English © 2025

sharp•en  (shär′pən), v.t., v.i. 

1. to make or become sharp or sharper.

• 1400–50; late Middle English; see sharp, -en¹

sharp′en•er, n. 

Collins Concise English Dictionary © HarperCollins Publishers::

sharpen / ˈʃɑːp^ən/ verb

1. to make or become sharp or sharper
2. to raise the pitch of (a note), esp by one chromatic semitone

ˈsharpener noun