'heterogeneity' originates from Greek, specifically the word 'heterogenēs,' where 'hetero-' meant 'different' and 'genēs' meant 'kind or type.'

'heterogenēs' transformed into the Medieval Latin word 'heterogeneitas,' and eventually became the modern English word 'heterogeneity.'

Initially, it meant 'different in kind or nature,' and this meaning has largely remained the same in modern usage.