IPA: //ˈaɪ.kʌp//
KK: /ˈaɪˌkʌp/
A small cup designed to fit the shape of the eye, used for applying liquid medicine or washing the eye.
She used an eyecup to rinse her eyes after getting dust in them.
Eyecup → The word is formed from "eye" (from Old English "ēage", meaning the organ of sight) and "cup" (from Old French "coup", meaning a small container). An eyecup is a small container designed to hold liquid for washing or bathing the eye.
Think of the 'eye' as the organ of sight and 'cup' as a small container — an eyecup is a container specifically for the eye.
No commonly confused words.