'nonankylosing' originates from English, specifically by combining the prefix 'non-' (from Old English/Latin usage meaning 'not') with 'ankylosing', which in turn comes from Greek 'ankylos' meaning 'crooked, bent, or fused'.

'ankylosing' developed via medical Latin/Neo-Latin formations from the Greek root 'ankylos' → Latinized as 'ankylosis' (stiffness, fusion) → English 'ankylosis' and the adjective-forming 'ankylosing'; the negating prefix 'non-' was attached in modern English to form 'nonankylosing'.

Initially the Greek root 'ankylos' conveyed 'crooked' or 'bent'; in medical Latin it came to denote 'stiffness' or 'fusion' of joints ('ankylosis'), and 'ankylosing' describes processes that cause such fusion; 'non-' negates that, yielding the current meaning 'not causing fusion'.