Tidal waves are caused by the gravitational fields of the sun, the moon and the earth. A tidal wave is a small, regularly occurring wave caused by the shifting of the tide.
Tides are an oceanic phenomenon caused primarily by the gravitational pull of moon, but they are also caused by the gravitational force of the sun, though to a lesser extent. Due to the moon's proximity to Earth, its gravitational field is able to move water, while inertia causes the water to continue flowing in the same direction. This leads to a shallow, long-lasting wave that increases the sea level along a shoreline horizontally.
The term "tidal wave" is colloquially used to refer to tsunamis; however, this is not completely accurate. Tsunamis are large waves caused by an enormous displacement of water. Underwater earthquakes and tectonic activity are often the cause of tsunamis, but landslides and meteorite impacts are also known to displace enough water. The scientific community rejects this definition of tidal wave because tsunamis are unrelated to the tide.
Storm surges are also sometimes referred to as tidal waves, colloquially. Storm surges are dramatic increases in water level caused by storms, and they are sometimes exacerbated by tidal forces.