late Middle English: from Latin aestimat- 'determined, appraised', from the verb aestimare. The noun originally meant 'intellectual ability, comprehension' (only in late Middle English), later 'valuing, a valuation' (compare with estimation). The verb originally meant 'to think well or badly of someone or something' (late 15th cent.), later 'regard as being, consider to be' (compare with esteem)