IPA: /ˈtʃɛkˌbɒks/
KK: /ˈtʃɛkˌbɑks/
A small square box on a form or webpage that can be marked to show a choice or option is selected.
Please check the box next to your preferred option on the form.
Checkbox → It is formed from "check" (from Old English *cecan*, meaning to check or inspect) and "box" (from Old English *box*, meaning a container). The word "checkbox" refers to a container used for marking a check or selection.
Think of a 'container' ('box') where you 'check' something off — that's what a checkbox is used for.
No commonly confused words.