Three colons stacked vertically, a logic operator.
U+2AF5TRIPLE VERTICAL BAR WITH HORIZONTAL STROKEU+2AF7TRIPLE NESTED LESS-THANU+2AF4TRIPLE VERTICAL BAR BINARY RELATIONU+2AF8TRIPLE NESTED GREATER-THANU+2AF3PARALLEL WITH TILDE OPERATORU+2AF9DOUBLE-LINE SLANTED LESS-THAN OR EQUAL TOU+2AF2PARALLEL WITH HORIZONTAL STROKEU+2AFADOUBLE-LINE SLANTED GREATER-THAN OR EQUAL TOU+2AF1DOWN TACK WITH CIRCLE BELOWU+2AFBTRIPLE SOLIDUS BINARY RELATIONU+2AF0VERTICAL LINE WITH CIRCLE BELOWU+2AFCLARGE TRIPLE VERTICAL BAR OPERATOR256 characters in the Supplemental Mathematical Operators Unicode block, from number 247.
U+2AF6TRIPLE COLON OPERATORU+2AF7TRIPLE NESTED LESS-THANU+2AF8TRIPLE NESTED GREATER-THANU+2AF9DOUBLE-LINE SLANTED LESS-THAN OR EQUAL TOU+2AFADOUBLE-LINE SLANTED GREATER-THAN OR EQUAL TOU+2AFBTRIPLE SOLIDUS BINARY RELATIONU+2AFCLARGE TRIPLE VERTICAL BAR OPERATORU+2AFDDOUBLE SOLIDUS OPERATORU+2AFEWHITE VERTICAL BARU+2AFFN-ARY WHITE VERTICAL BAR