onycho

Onycho is a combining form used in medical terminology to denote relation to nails or claw-like structures. It derives from the Greek word for nail or claw and is related to the more common combining form onych-, though some sources treat onycho- as a variant spelling or usage.

In modern clinical language the spelling onych- is predominant, but onycho- may appear in older texts, dictionaries, or in certain compound words where phonetic considerations or etymological conventions lead to the variant. Both forms are ultimately based on the same root and refer to nails or claw-like structures in humans and other animals.

Common terms built from this root include onychomycosis (fungal infection of the nails), onycholysis (separation of the nail from the nail bed), onychitis or onychitis (inflammation of the nail or nail folds), onychodystrophy (abnormal nail growth or structure), and onychopathy (nail disease or disorder). These terms illustrate how the root functions to name nail-related conditions and anatomy.

In anatomy and biology, the root sometimes appears in broader contexts to indicate nail-like or claw-like features, though in everyday medical usage the onych- form is more prevalent than any standalone use of onycho. The term is primarily of interest in etymology, medical terminology, and the study of nail diseases rather than as an independent concept.

See also: onych-, onychology, nail (anatomy).