Shimon the root of the name Shimon is shema' "hear." 

The Midrash states that the name Shimon have reference to the future redemption by relating it to the verse, "And HaShem heard their cries, and HaShem remembered His covenant with Avraham, Yitzchak and Yaakov" (Shemot 2:24)

Encampment Position - South

Shimon was positioned between Reuven and Gad for his own spiritual protection.  Shimon had received no explicit blessing from his father Yaakov, who was angry that Shimon had the initiative in destroying Shechem and in selling Yosef.  Moshe also chose not to bestow upon this Tribe a separate blessing, because he was angry that its members had participated in the sin of Shittim.  Because Shimon was bereft of blessings, HaShem stationed his Tribe where it would benefit from its neighbors' spiritual powers, which called forth Divine Mercy and Strength.