Precipitation is water that usually comes down to us from the clouds. Such precipitation comes in the form of rain, snow, hail or sleet. Gravity pulls it down to earth. Precipitation is therefore an important part of the water cycle.
Precipitation does not have to fall from the sky, however. Our air always contains some water. Sometimes it's so much that it forms the grey mist. But whether you see the water in the air or not, it can precipitate on something, i.e. attach itself to something. If it is warm enough, it collects in small drops as dew. When it is cold, the water forms frost or hoarfrost on meadows and plants. Cars, or at least their windows, are sometimes covered with a layer of ice.
How much precipitation there is in an area varies greatly. When it comes to the precipitation that usually falls, we talk about climate. In the tropics, i.e. in the climatic region around the equator, it can often be hot and humid. In deserts, on the other hand, there is very little precipitation.
The weather is something similar, but we speak of weather when we think of just one day or a few weeks. So then it depends on how much it rains or snows during that time. This can be quite different from the long-term average, the mean.