'ankylosis' originates from Greek, specifically the word 'ankylōsis', where the element 'ankyl-' meant 'bent' or 'crooked' (implying stiffness or fusion).

'ankylōsis' was adopted into Late Latin/medical Latin as 'ankylosis' and then entered English in medical usage with little change in form.

Initially it referred to the condition of being bent or fused; over time it came to denote specifically the medical condition of joint or tooth fusion causing stiffness and immobility.