'heat-permeable' originates from the combination of 'heat' and 'permeable', where 'permeable' comes from Latin 'permeabilis', meaning 'that can be passed through'.

'Permeable' changed from the Latin word 'permeabilis' and eventually became the modern English word 'permeable'.

Initially, 'permeable' meant 'that can be passed through', and this meaning has largely remained the same in modern usage.