The Spanish word 'tributable' meaning 'taxable' comes from combining the Spanish noun 'tributo' (tribute, tax) with the suffix '-able' meaning 'able to be'. The word 'tributo' itself comes from Latin 'tributum' meaning 'tax' or 'tribute', which was derived from the Latin verb 'tribuere' meaning 'to distribute'. This etymology reflects how taxes were seen as a distribution or allocation of resources to the governing authority.

Some related simpler Spanish words include 'tributo' (tribute, tax), which is the base word from which 'tributable' is formed. Another related word is 'tributar' (to pay tribute), which shares the same Latin root. These words maintain the core meaning related to taxation and paying tribute.

Several English words share the same Latin origin, including 'tribute', 'tributary', and 'contribute'. A 'tribute' is a payment made to show respect or allegiance, while a 'tributary' is a stream that contributes water to a larger river - both reflecting the original Latin meaning of distribution. 'Contribute' literally means 'to give together with others', maintaining the sense of distribution or giving. The English suffix '-able' is also cognate with the Spanish '-able', both meaning 'capable of' or 'suitable for'.