鉅 is not used independently in modern Chinese. It is an old written variant of 巨 (huge), simplified today as 钜; in classical texts it also meant hard iron or a barbed hook. It joins the metal radical 钅 (traditional 釒) with the phonetic 巨.
register
Archaic spelling; encountered in old texts, personal and place names, and etymology notes, not in modern writing.
Components
radical
釒jīn
metal; gold
The metal radical (full 釒, simplified 钅) on the left fits the 'hard iron / barbed hook' sense; it is the form behind metal-working characters.
