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Definition(s) of “Z”
Z 1 |zē| (also z)
noun ( pl. Zs or Z's )
1 the twenty-sixth letter of the alphabet.
• denoting the next after Y in a set of items, categories, etc.
• denoting a third unknown or unspecified person or thing : X sold a car to Y (a car dealer) who in turn sold it to Z (a finance company).
• (usu. z ) the third unknown quantity in an algebraic expression. [ORIGIN: the introduction of x, y, and z as symbols of unknown quantities is due to Descartes (see X 1 ).]
• (usu. z ) denoting the third axis in a three-dimensional system of coordinates : [in combination ] the z -axis.
2 a shape like that of a capital Z : [in combination ] the same old Z-shaped crack in the paving stone.
3 used in repeated form to represent the sound of buzzing or snoring.
PHRASES
catch some (or a few) Zs informal get some sleep : I'll go back to the hotel and catch some Zs.
Z 2
symbol Chemistry
atomic number.
atomic number
noun Chemistry & Physics
the number of protons in the nucleus of an atom, which determines the chemical properties of an element and its place in the periodic table. (Symbol: Z)