'smooth-grained' originates from English, specifically the words 'smooth' and 'grain', where 'smooth' comes from Old English 'smōþ' meaning 'even, not rough' and 'grain' ultimately from Latin 'granum' meaning 'seed' but used in English to denote 'texture' or 'fibre'.

'smooth' developed from Old English 'smōþ' and 'grain' from Old French/Latin roots ('grain' < Old French 'grain' < Latin 'granum'); the compound 'smooth-grained' emerged as a Modern English descriptive compound combining these elements to describe texture.

Initially 'smooth' meant 'even, not rough' and 'grain' referred to 'seed' or 'particle' and later 'texture'; combined as 'smooth-grained' the meaning stabilized to 'having an even or fine texture' in reference to materials.