1560s, "valuation," from Latin aestimatus "determine the value of," figuratively "to value, esteem," verbal noun from aestimare (see esteem (v.)). Earlier in sense "power of the mind" (mid-15c.). Meaning "approximate judgment" is from 1580s. As a builder's statement of projected costs, from 1796.

1530s, "appraise the worth of," from Latin aestimatus, past participle of aestimare "to value, appraise" (see esteem (v.)). Meaning "form an approximate notion" is from 1660s. Related: Estimated; estimates; estimating.

also over-estimate, "estimate too highly, overvalue," 1768, from over- + estimate (v.). Related: Over-estimated; over-estimating.

1902, a blending of guess (v.) and estimate (v.). Related: Guesstimated; guesstimating. As a noun from 1906.

1812, "to estimate at too low an amount," from under + estimate (v.). Meaning "to rank too low, undervalue" is recorded from 1850. Related: Underestimated; underestimating.

"estimate erroneously," 1778, from mis- (1) "badly, wrongly" + estimate (v.). Related: Misestimated; misestimating. As a noun by 1843 (misestimation is by 1809).

1570s, "above value, too valuable for exact estimate," from in- (1) "not" + value (v.) "estimate the worth of" + -able. It also has been used in a sense "without value, worthless" (1630s, from in- + valuable). Related: Invaluably.

also low-ball, "report or estimate lower," from low (adj.) + ball (n.1).

mid-15c., "estimate the value of," also "think highly of," probably from value (n.). Related: Valued, valuing.

"erroneous calculation or estimate," 1720, from mis- (1) "bad, wrong" + calculation.