'actinobacilli' originates from New Latin, specifically the word 'actinobacillus,' where 'actino-' meant 'ray' and 'bacillus' meant 'little rod.'

'actinobacillus' changed from the New Latin word 'actinobacillus' and eventually became the modern English word 'actinobacilli.'

Initially, it referred to a specific genus of bacteria, and this meaning has largely remained the same in modern usage.