Ejecta (from the Latin: "things thrown", singular ejectum) refers to particles ejected from an area. In volcanology, in particular, the term refers to particles that came out of a volcanic vent, traveled through the air or under water, and fell back on the ground surface or on the ocean floor. Ejecta can consist of:

1. Juvenile particles - (fragmented magma and free crystals)
2. Cognate or accessory particles - older volcanic rocks from the same volcano
3. Accidental particles - derived from the rocks under the volcano