Real Dictionary

Z
variable noun: Z is the twenty-sixth and last letter of the English alphabet.

Z in American English
noun: the 26th letter of the English alphabet, a consonant

Z in American English 1
the twenty-sixth and last letter of the English alphabet: via Latin from the Greek zeta
abbreviation: zenith distance
abbreviation: zone

Z in American English 2
atomic number
the third of a set of unknown quantities, x and y usually being the first two
symbol: an unknown quantity or variable
symbol: the 26th in order or in a series, or, when I is omitted, the 25th

Z in American English 3
zenith distance
zetta-

z in British English
abbreviation for: Zambia (international car registration)
noun: the 26th and last letter and the 20th consonant of the modern English alphabet
symbol for: any unknown, variable, or unspecified factor, number, person, or thing
symbol for: the z- axis or a coordinate measured along the z-axis in a Cartesian or cylindrical coordinate system

z. in American English
abbreviation: zero