Yes, it indicates the general level of the character. Typically it is a lowercase x to amplify the number, but it goes either way.
I have a level 94 water priest, but it levels decently quickly and I don't always pay attention to my signature, so I leave it as 9x to indicate it's general level.
KaozReaper - for-hire Alchemist
Whitept - 14x Fire Killer
Forgotten - 11x Fire Seer (8x RB Xaolan)
TheScholar - 14x Perfect Water Priest (13x RB Niss)
Leo - UnitedLeos
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