<b>J</b>ensen Ackles * <b>J</b>ared Padalecki = <b>J</b>Squared
This word stems from the SPN fan community.
It is a term that is often used in connection with slash fanworks. In literary works of the RPS category the abreviation for the pairing Jensen/Jared is JSquared.
JSquared are my OTP.