xi

In a sentence

• Xi to litera stosowana w alfabecie greckim.

  Xi is a letter used in the Greek alphabet.

  Here, 'xi' is referred to as a Greek letter name.

• Czytałem książkę, w której bohater miał na imię Xi.

  I read a book where the protagonist was named Xi.

  Here, 'xi' is used as a proper noun, referring to a name.

• W matematyce xi może reprezentować zmienną.

  In mathematics, xi can represent a variable.

  Here, 'xi' serves as a mathematical symbol or variable name.