'strongly-grown' originates from the combination of 'strongly' and 'grown', where 'strongly' is derived from 'strong', meaning 'having great physical power', and 'grown' is the past participle of 'grow', meaning 'to increase in size or strength'.

'strongly' changed from Old English 'stranglice', and 'grown' from Old English 'grōwan', eventually forming the modern English compound adjective 'strongly-grown'.

Initially, 'strongly' meant 'with great force', and 'grown' meant 'increased in size', but together they evolved to describe something that has developed significantly in strength.