'hobnail' originates from Middle English, specifically a compound of 'hob' + 'nail', where 'hob' meant 'a small knob or projection' and 'nail' meant 'a metal nail'.

'hobnail' changed from Middle English forms such as 'hobbenail' or 'hobnenail' (a compound of elements meaning 'hob' + 'nail') and eventually became the modern English word 'hobnail'.

Initially it referred to 'a nail with a small knob', but over time it came to mean 'a short heavy nail used in the sole of a boot' and by extension 'a boot fitted with such nails'.