Earhole is a rough, informal word for your ear. British speakers use it more than American ones. A child, a football crowd, or someone being blunt might say it instead of ear, or talk about a clip round the earhole — a smack on the side of the head. Though actually, the word also names the opening that leads into the ear, and people slide between “the whole ear” and “the hole” without noticing. It is not the word you take to a doctor, and it can sound rude in a classroom. In Middle English it was already ear plus hole; the picture is simply the hole of the ear.