'top-notch' originates from the English phrase 'top notch,' where 'top' meant 'highest' and 'notch' referred to a 'level or degree.'

'top notch' was used in the 19th century to describe something of the highest quality and eventually became the modern English adjective 'top-notch.'

Initially, it meant 'the highest level or degree,' but over time it evolved into its current meaning of 'of the highest quality.'