Strictly speaking, it's Black's response to a particular opening move by White, that's known as the Sicilian Defence.
One of the most popular opening moves for White is 'king's pawn to e4'. This gives White a strong strategic presence in the middle of the board. Black will often respond with 'bishop's pawn to c5', and this is the Sicilian Defence.
According to Penn State University, this "attempts to throw the white off guard and turn black's disadvantage into an advantage through white's mistakes. However, this opening ... is dependent on good technique and tactics."
The Sicilian Defence was first documented as long ago as 1594, by the Italian chess player and theoretician Giulio Cesare Polerio, who was born in the central Italian region of the Abruzzo and had no obvious connection with Sicily. Its now–familiar name was first used in 1813 by the English master Jacob Henry Sarratt, referring to an old Italian manuscript that used the phrase il gioco siciliano ('the Sicilian game').
© Haydn Thompson 2022