'uneven-grained' originates from Modern English, specifically the compound of 'uneven' and 'grained', where 'uneven' is formed from the prefix 'un-' meaning 'not' and 'even' meaning 'level', and 'grained' comes from 'grain' meaning 'seed/particle'.

'uneven' derives from Old English elements 'un-' + 'efen' (level); 'grain' comes via Old French 'grain' from Latin 'granum' meaning 'seed'. These elements existed separately in earlier English and were combined in Modern English to form descriptive compounds such as 'uneven-grained'.

Initially, the components meant 'not level' (uneven) and 'seed/particle' (grain); over time the compound came to be used specifically for materials to mean 'having non-uniform grain size or pattern'.