'serendipitous' originates from the English word 'serendipity', which was coined by Horace Walpole in 1754, inspired by the Persian fairy tale 'The Three Princes of Serendip', where the princes made discoveries by accident.

'Serendipity' was coined in the 18th century and evolved into 'serendipitous' in the 20th century, eventually leading to the adverb 'serendipitously'.

Initially, it referred to the occurrence of events by chance in a happy way, and this meaning has largely remained the same in modern usage.