onych

Onych is a combining form used in medical and scientific terminology to denote nails or claw-like structures. It derives from the Greek word onux (or onychos), meaning nail or claw, and appears in a broad range of terms across dermatology, podiatry, and zoology.

In human medicine, onych- forms terms that relate to nails and nail conditions. Examples include onychomycosis (fungal infection of the nails), onycholysis (separation of the nail plate from the nail bed), and onychia or onychitis (inflammation of the nail or nail matrix). The prefix also appears in onychopathy (nail disease or disorder), onychophagia (nail-biting), onychorrhexis (splitting of the nail), and onychoplasty (surgical repair or reconstruction of the nail). These terms are used across clinical descriptions, diagnoses, and procedures.

In zoology, the root appears in the name Onychophora, the velvet worms, whose name means “claw bearers” or “nail-bearing,” reflecting their claw-like appendages. The same root is used to describe animal claws or claw-like structures in other contexts, illustrating the breadth of its descriptive utility.

As a linguistic element, onych is generally treated as a combining form rather than a standalone word in English. It combines with Greek or Latin roots to create terms related to nails, claws, or claw-like anatomical features, and it is encountered primarily in medical terminology and scientific nomenclature.