'closely-split' originates from the combination of 'close' and 'split', where 'close' meant 'near' and 'split' meant 'to divide'.

'closely-split' evolved from the Middle English word 'spliten', which meant 'to divide', and 'close', which has retained its meaning over time.

Initially, 'split' meant 'to divide', and 'close' meant 'near'. The combination now describes a division with minimal difference.