IPA: /ˈkiːˌpʌnʧər/
KK: /kipʌnʧər/
A person who uses a machine to enter data by pressing keys, often on a computer or similar device.
The keypuncher worked diligently to input all the data into the system.
Keypuncher → It is formed from "key" (from Old English *cæg*, meaning a device for opening) and "puncher" (from "punch" which comes from Latin *pungere*, meaning to pierce). A keypuncher is a person who uses a device to pierce holes in cards or paper to input data.
Think of a 'key' as a device that opens things and 'punching' as piercing holes — a keypuncher is someone who uses a key-like device to punch holes for data input.