Whats the meaning of bible/Revelations 22:2? And on either side of the river was there a tree of life, which bare twelve manner of fruits, and yielded her fruit every month; And the leaves of the tree were for the healing of the nations.

In the midst of the street signifies the Kingdom of God where there is the tree of life or there is eternal life which has twelve fruits and is yielding every month. This expresses abundance in that place. The leaves of the tree were for healing which shows that in that place there is no sickness since there is continued health.