'tomentum' originates from Latin, specifically the word 'tomentum', where 'tomentum' meant 'a stuffing of wool or a cushion of wool'.

'tomentum' changed from Medieval/Latin usage (Late Latin/Medieval Latin 'tomentum') and was adopted into English (from roughly the 17th century) particularly in scientific and botanical contexts, eventually becoming the modern English 'tomentum'.

Initially, it meant 'a stuffing of wool' or 'wool padding', but over time it evolved into the current primary meaning of 'a covering of short, matted hairs on plants'.