'aquopentammine' originates from modern chemical nomenclature (New Latin/International Union of Pure and Applied Chemistry conventions), specifically combining the prefix 'aquo-' ultimately from Latin 'aqua' where 'aqua' meant 'water', the combining form 'penta-' from Greek 'penta' where 'penta' meant 'five', and 'ammine' from 'amine' (related to 'ammonia') indicating coordinated NH3 ligands.

'aquopentammine' evolved by concatenation of older component names used in coordination chemistry: originally separate terms 'aqua' (for water ligand) and 'pentammine' (five ammine ligands) were used; over time these components were joined in systematic names (e.g., 'aqua pentammine cobalt') to form the modern fused form 'aquopentammine'.

Initially the elements of the term separately referred simply to 'water' and 'five ammonia ligands'; over time the fused form came to serve as a standardized naming fragment meaning 'a complex part containing 1 H2O and 5 NH3 ligands'.