'yawn' originates from Old English, specifically the word 'geonian,' where 'geo-' meant 'to gape or open wide.'

'geonian' transformed into the Middle English word 'yawn,' and eventually became the modern English word 'yawn.'

Initially, it meant 'to open wide,' but over time it evolved into its current meaning of 'to open one's mouth wide due to tiredness or boredom.'