This is the weapon of Skyness. The Lily stands for freedom. Skyness is a free trading city with an own government, whose citizens cannot be enslaved, even the poorest. (Though it doesn't keep people from exploiting the poor, which principally is also some kind of slavery) Skyness is also a very crazy and tumultous city, so you actually can't depend on the city to always be like it is, the only permanent thing of Skyness is actually, that the city changes (Let aside it's weapon).
The three summits stand for the three mountains on which Skyness is built. The left and the right stand for the port of skyness and for Sylphtown, the one in the middle for the seat of the High Council of Skyness, the summit, in which the Council Building stands, in which the High Council of Skyness meets.
If you want to know more about Skyness, read it here.