Z1 [z?d, US zi:]
(also z)
¦ noun (plural Zs or Z's)
1. the twenty-sixth letter of the alphabet.
2. denoting the next after Y in a set of items, categories, etc.
3. (usu. z) the third unknown quantity in an algebraic expression.
denoting the third axis in a three-dimensional system of coordinates.
4. used in repeated form to represent buzzing or snoring.
Phrases
catch some (or a few) Zs N. Amer. informal get some sleep.
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Z2
¦ abbreviation Zambia (international vehicle registration).
¦ symbol Chemistry atomic number.