'infrequently-assembled' originates from the combination of 'infrequent' and 'assemble', where 'infrequent' means 'not occurring often' and 'assemble' means 'to gather or put together'.

'infrequent' changed from the Latin word 'infrequens' and 'assemble' from the Latin word 'assimulare', eventually becoming the modern English words 'infrequent' and 'assemble'.

Initially, 'infrequent' meant 'not crowded' and 'assemble' meant 'to make similar', but over time they evolved into their current meanings of 'not occurring often' and 'to gather or put together'.