Wedges:

A wedge is drawn by converging trend lines, indicating tightening price action. The trend lines, in this case, show that the highs and lows are either rising or falling at a different rate.

It might mean that a reversal is impending, as the underlying trend is getting weaker. A wedge pattern may be accompanied by decreasing volume, also indicating that the trend might be losing momentum.

Rising wedge:

The rising wedge is a bearish reversal pattern. It suggests that as the price tightens up, the uptrend is getting weaker and weaker, and may finally break through the lower trend line.