'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 'Serendip' referred to Sri Lanka.

'serendipity' evolved from the tale's name 'Serendip,' and the suffix '-ous' was added to form 'serendipitous,' eventually leading to the adverb 'serendipitously.'

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