We found 16 dictionaries that define the word interstellar medium:

General (9 matching dictionaries)

1. interstellar medium: Collins English Dictionary
2. interstellar medium: Vocabulary.com
3. interstellar medium: Wiktionary
4. interstellar medium: Dictionary.com
5. Interstellar medium: Wikipedia, the Free Encyclopedia
6. interstellar medium: FreeDictionary.org
7. interstellar medium: Mnemonic Dictionary
8. interstellar medium: TheFreeDictionary.com
9. interstellar medium: Rhymezone

Computing (1 matching dictionary)

10. interstellar medium: Encyclopedia

Science (4 matching dictionaries)

11. Interstellar Medium: Eric Weisstein's World of Astronomy
12. Imagine the Universe! Dictionary (No longer online)
13. Interstellar Medium: Extragalactic Astronomy
14. INTERSTELLAR MEDIUM: Zoom Astronomy Glossary

Tech (2 matching dictionaries)

15. High-Energy Astrophysics (No longer online)
16. JPL Terms (No longer online)

(Note: See interstellar_mediums as well.)

Definitions from Wiktionary (interstellar medium) ▸ noun:  (astronomy) The matter that exists in the space between star systems in a galaxy, including gas, dust, and cosmic rays. Similar: intergalactic medium, circumgalactic medium, interstellar space, interplanetary space, intershell, interspace, intermedium, intermundium, interstitium, Local Interstellar Cloud, more... Opposite: intergalactic space, vacuum, emptiness, void ▸ Words similar to interstellar medium ▸ Usage examples for interstellar medium ▸ Idioms related to interstellar medium ▸ Wikipedia articles (New!) ▸ Words that often appear near interstellar medium ▸ Rhymes of interstellar medium ▸ Invented words related to interstellar medium