'second-class' originates from the combination of 'second,' meaning 'next after the first,' and 'class,' meaning 'a category or division.'

'Second-class' evolved from the use of 'class' in the 19th century to denote different levels of service or quality, particularly in transportation.

Initially, it referred to a literal second category in services, but over time it also gained a metaphorical sense of inferiority.