endosome

https://doi.org/10.1351/goldbook.13111
Intracellular smooth surfaced vesicle in which endocytosed material passes on its way to the lysosomes.
Source:
PAC, 2012, 84, 1113. (IUPAC glossary of terms used in immunotoxicology (IUPAC Recommendations 2012)) on page 1160 [Terms] [Paper]