zero

zero [zir′ō, zē′rō]

n.

pl. zeros or zeroes [Fr zéro < It zero < Ar ṣifr,CIPHER]

1. the symbol or numeral 0, representing the complete absence of any quantity or magnitude

2. the point, marked 0, from which positive or negative quantities are reckoned on a graduated scale, as on a thermometer; specif.,

a) on a centigrade thermometer, the freezing point of water

b) on a Fahrenheit thermometer, a point 32° below the freezing point of water

3. a temperature that causes a thermometer to register zero

4. the point intermediate between positive and negative quantities

5. nothing

6. the lowest point [his chances of success sank to zero]

7. Gunnery a sight setting for a range, allowing for both elevation and windage

adj.

1. of or at zero

2. without measurable value

3. Informal not any; no [a snack having zero cholesterol]

4. Aeron.

a) designating or of a ceiling that is at or near the ground, specif. one at a height of fifty feet or lower

b) designating or of visibility along the ground regarded as within the limit of a few feet

5. Linguis. designating a hypothetical inflectional form [the plural of deer is said to be formed by the addition of a zero allomorph of the plural morpheme]

vt.

zeroed, zeroing

to adjust (an instrument, etc.) to a zero point or to an arbitrary point from which all positive and negative readings are to be measured

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zero in

1. to adjust the zero of (a gun)

2. to aim (a gun) or concentrate (firepower) directly at or on (a target)

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zero in on

1. to adjust gunfire so as to be aiming directly at (a target)

2. to concentrate attention on; focus on