
absolute temperature 
temperature measured on a scale in which zero equals the lowest temperature that can be obtained physically. 
absolute value 
the magnitude of a real number irrespective of its sign; distance of a real number from zero. [1/2 definitions] 
Arabic numeral 
any of the symbols for the numbers one through nine, including zero; 0, 1, 2, 3, 4, 5, 6, 7, 8, or 9. 
Arcturus 
an orange star in the constellation Boötes, having a magnitude of zero. 
C^{1} 
abbreviation of "Celsius," or "Centigrade," of, pertaining to, or designating a temperature scale on which zero degrees is the freezing point and one hundred degrees is the boiling point of water. 
Celsius 
of, pertaining to, or designating a temperature scale on which zero degrees is the freezing point and one hundred degrees is the boiling point of water; centigrade. (abbr.: C) 
cipher 
the sign 0; naught or zero. [1/7 definitions] 
countdown 
the act or procedure of counting in reverse in preparation for some event, such as the firing of a rocket, to occur at "zero". [1/2 definitions] 
deflection 
in physics, the movement away from zero of the indicator of a measuring instrument. [1/3 definitions] 
digit 
any of the numbers from zero through nine. [1/2 definitions] 
integer 
a positive or negative whole number or zero; a whole number as opposed to a fraction. 
Kelvin 
a thermodynamic temperature scale whose degree intervals correspond to those of the Celsius scale and in which zero degrees, or absolute zero, is equal to 273.15 degrees Celsius. [1/3 definitions] 
naught 
the number zero. [1/3 definitions] 
negative 
indicating a number or quantity less than zero. (Cf. positive.) [2/14 definitions] 
nil 
nothing; zero. 
nonzero 
indicating a quantity or value other than zero. 
nothing 
zero. [1/7 definitions] 
o 
the cipher zero. [1/4 definitions] 
one 
the number that follows zero and precedes two in the sequence of cardinal numbers. [1/11 definitions] 
pH 
a symbol for a measure of the degree of alkalinity or acidity of a solution, determined by the concentration or activity of hydrogen ions therein (often fol. by a number, with seven indicating neutrality, zero to six indicating acidity, and eight to fourteen indicating alkalinity). 
photon 
the fundamental unit of electromagnetic energy with zero mass, no electrical charge, and a spin of one, usu. regarded as an elementary particle. 

