A pinna that is fully absent is termed:

The term that defines a fully absent pinna is 'anotia.' Anotia specifically refers to the congenital absence of the external ear, which includes the pinna. This condition is usually present at birth and can vary in severity, sometimes accompanied by other ear malformations or associated syndromic conditions.

Microtia, while related, refers to a condition where the pinna is underdeveloped or malformed but not completely absent. Atresia refers to the closure or absence of the ear canal, which is a different anatomical issue. Collapse usually describes the situation where the pinna folds inwards, often due to external pressure or significant tissue loss, rather than a total absence. Understanding these terms and their specific definitions is essential for grasping conditions related to ear development and their implications in audiology and hearing instrument fitting.