Scavenging can refer to different processes depending on the context. Here are some definitions:

1. In the context of engines, scavenging is the process of replacing the exhaust gas in a cylinder of an internal combustion engine with the fresh air/fuel mixture (or fresh air, in the case of direct-injection engines) for the next cycle). The scavenge or scavenging port refers to that port through which clean air enters the cylinder, the exhaust port through which it leaves).

2. In the context of animals, scavenging refers to the act of searching for food or other objects in other peoples rubbish or in the remains of dead animals.

3. In the context of recycling or refuse containers, scavenging is the act of unauthorized persons going through them to take recyclables or other materials.

4. In the context of chemistry, scavenging can refer to the removal of an undesirable constituent from a substance or region by chemical or physical means.

5. In the context of metallurgy, scavenging can refer to the process of cleaning and purifying molten metal by taking up foreign elements in chemical union.

6. In the context of cleaning, scavenging can refer to the act of removing dirt, refuse, or other unwanted material from an area.

In summary, scavenging can refer to the process of replacing exhaust gas with fresh air/fuel mixture in engines, searching for food or other objects in other peoples rubbish or in the remains of dead animals, or going through recycling or refuse containers to take recyclables or other materials. It can also refer to the removal of an undesirable constituent from a substance or region by chemical or physical means, the cleaning and purifying of molten metal, or the act of removing dirt, refuse, or other unwanted material from an area.