Translation guide
The external part of the ear; the auricle. In everyday English, this is usually just called the 'ear' (the visible part). Japanese uses 耳介 (jikai) in medical contexts, but in daily life, 耳 (mimi) refers to both the outer ear and the organ of hearing.
Referring specifically to the external, visible part of the ear (the auricle/pinna) in medical or biological contexts.
In casual conversation, when an English speaker might say 'pinna' to mean the visible part of the ear, Japanese simply uses the general word for ear.
In everyday Japanese, 耳 (mimi) covers both the outer ear and the organ of hearing. Context usually makes it clear. If you need to specify the outer part, you can say (mimi no sotogawa, 'the outside of the ear').
In most daily situations, 耳 (mimi) is sufficient. If you need to be precise (e.g., describing an injury), you can add 外側 (sotogawa, 'outside') or use the anatomical term 耳介 (jikai).
The shape of the pinna varies from person to person.
An alternative anatomical term for the pinna, less common than 耳介 but still used in medical literature.
The cartilage of the pinna is elastic.
You have big ears. (referring to the pinnae)
Decorate the outer ear with piercings.