TABLE 2.
Quick‐reference card on EV nomenclature and related terms.
| Term | Definition | Usage |
|---|---|---|
| Extracellular vesicles (EVs) | Particles that are released from cells, are delimited by a lipid bilayer, and cannot replicate on their own. | Recommended |
| Non‐vesicular extracellular particles (NVEPs) | Multimolecular assemblies that are released from cells and do not have a lipid bilayer (non‐vesicular extracellular particle fraction). | Recommended |
| Extracellular particles (EPs) | Umbrella term for all particles outside the cell, including EVs and NVEPs. | Recommended |
| EV mimetic | EV‐like particles that are produced through direct artificial manipulation. This term is preferred over ‘exosome‐like vesicles’ and similar terms that imply specific biogenesis‐related properties. | Recommended |
| Artificial cell‐derived vesicles (ACDVs) | EV mimetics that are produced in the laboratory under conditions of induced cell disruption, such as extrusion. | Recommended |
| Synthetic vesicles (SVs) | EV mimetics that are synthesized de novo from molecular components or made as hybrid entities, e.g., fusions between liposomes and native EVs. | Recommended |
| Small EVs (operational term) | Based on the diameter of the separated particles, small EVs are often described as <200 nm in diameter. However, measured diameter is related to the specific characterization method. | Recommended, but caution required |
|
Large EVs (operational term) |
Based on the diameter of the separated particles, large EVs are often described as >200 nm in diameter. However, measured diameter is related to the specific characterization method. | Recommended, but caution required |
| Other ‘operational terms’ | Physical characteristics: e.g., diameter: small extracellular vesicles (sEVs), large EVs (lEVs), density: low, medium, high (defined ranges). Biochemical composition: e.g., contains a specific (macro)molecule, such as a protein. Cellular origin and/or conditions under which EVs were generated: terms that highlight specific aspects of biogenesis such as molecular mechanisms, energy‐dependence (or lack thereof) and functional state of the parent cell related to stress or death. | Recommended, but caution required |
| Exosome | Biogenesis‐related term indicating origin from the endosomal system. Unless subcellular origin can be demonstrated, it is likely that a broad population of EVs is being studied, not exosomes specifically. Exosomes represent a subtype of small EVs: the diameter of intraluminal vesicles of endosomes is generally smaller than 200 nm. | Discouraged unless subcellular origin can be demonstrated |
| Ectosome | Biogenesis‐related term indicating origin from the plasma membrane. Unless subcellular origin can be demonstrated it is likely that a broad population of EVs is being studied, not ectosomes specifically. Ectosomes can have a wide range of sizes, including sizes similar to those of exosomes. | Discouraged unless subcellular origin can be demonstrated |
| Microvesicle | Biogenesis‐related term indicating origin from the plasma membrane. However, historically, the term has often been used to designate large EVs or all EVs, whatever their subcellular origin. This term can therefore lead to confusion. | Discouraged |
| Exosome‐like vesicles | As ‘exosome’ is a biogenesis‐related term indicating origin from the endosomal system, this and similar terms are discouraged for synthesized EV mimetics. | Discouraged |