'fir-related' originates from the English word 'fir,' which refers to a type of evergreen tree, combined with the suffix '-related,' indicating association or connection.

The term 'fir' comes from the Old English word 'fyrh,' which referred to a coniferous tree, and 'related' is derived from the Latin 'relatus,' meaning 'brought back.'

Initially, 'fir' referred specifically to the tree species, and 'related' meant 'connected.' The combination now signifies anything associated with fir trees.