In hydrology , infiltration refers to the maximum rate at which a soil can absorb precipitation. This is based on the initial moisture content of the soil or on the portion of precipitation that enters the soil. In soil science, the term refers to the process by which water enters the soil, generally by downward flow through all or part of the soil surface. The rate of entry relative to the amount of water being supplied by precipitation or other sources determines how much water enters the root zone and how much runs off the surface.
1. the abnormal entry of a substance (infiltrate) into a cell, tissue, or organ. Examples of infiltrates are blood cells, cancer cells, fat, or starch.
2. the injection of a local anaesthetic solution into the tissues to cause local anaesthesia.