Exosome

Part of speech: noun

Definitions

1. A tiny membrane-bound vesicle that a cell releases into its surroundings, carrying proteins, RNA and other molecules to nearby or distant cells
2. A minute sac shed from a cell into the extracellular fluid, containing molecular cargo that can be taken up by other cells during communication
3. Small vesicle secreted by cells that transports biological material such as genetic fragments and signaling proteins between cells in the body

Etymology: Exosomes are tiny membrane-bound sacs that cells release into the fluid around them, and the name was built in the modern laboratory from two Greek-derived pieces. The first, "exo-", comes from the Greek "exō," meaning "outside," which marks the sac as something a cell pushes out of itself rather than keeps inside. The second, "-some," comes from the Greek "sōma," meaning "body," and in biology it is used to name a small body or particle inside or near a cell, as in "ribosome" or "lysosome." Put together, the term describes a small body that lies outside the cell. The word is a technical coinage rather than an ancient one, so no classical writer ever used it; it was formed by scientists from older Greek building blocks to label a structure they needed to name.

Synonyms: extracellular vesicle