'informally-gathered' originates from the combination of 'informal' and 'gathered'. 'Informal' comes from Latin 'informalis', where 'in-' meant 'not' and 'formalis' meant 'formal'. 'Gathered' comes from Old English 'gadrian', meaning 'to bring together'.

'informally-gathered' evolved from the combination of 'informal' and 'gathered', which were used separately in Middle English and eventually combined in modern English.

Initially, 'informal' meant 'not formal', and 'gathered' meant 'brought together'. The combined term 'informally-gathered' now describes a group assembled without formalities.