X (disambiguation)

X or χ (the letter "chi") may refer to:
 * The χ-Blade, a legendary weapon introduced in Kingdom Hearts Birth by Sleep
 * The Recusant's Sigil, represented as an X
 * Hunter-X, a powerful enemy ship in Kingdom Hearts II
 * Luxord, number X in Organization XIII
 * Kingdom Hearts χ, an upcoming Kingdom Hearts game exclusive to PC browsers