What is the meaning of the word "y"?

Definitions:

  1. Abbreviation for the word 'Yes'. copy to clipboard ABBREVIATION
  2. An algebraic expression. copy to clipboard NOUN
  3. The twenty-fifth letter of English dictionary. copy to clipboard NOUN
  4. the Y-axis or a coordinate measured along the Y-axis in a Cartesian coordinate system. copy to clipboard NOUN

Synonyms: