Too large, great, or difficult to measure or calculate; extremely vast or intense.
From the prefix 'im-' (not) combined with 'measurable' from Old French 'mesurer' and Latin 'mensurare' (to measure). The root 'mensura' means measure, which also gives us 'meter' and 'mensuration.'
The ancient Romans were obsessed with measuring everything for their empire—roads, taxes, armies. The word 'immeasurable' basically means 'this is so huge that even Roman engineers would give up trying to measure it!' It's how Latin speakers expressed being blown away.
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