We found 24 dictionaries that define the word ommatidium:

General (19 matching dictionaries)

1. ommatidium: Merriam-Webster
2. ommatidium: Oxford Learner's Dictionaries
3. ommatidium: American Heritage Dictionary of the English Language
4. ommatidium: Collins English Dictionary
5. ommatidium: Vocabulary.com
6. ommatidium: Wordnik
7. ommatidium: Wiktionary
8. ommatidium: Webster's New World College Dictionary, 4th Ed.
9. ommatidium: The Wordsmyth English Dictionary-Thesaurus
10. ommatidium: Infoplease Dictionary
11. ommatidium: Dictionary.com
12. Ommatidium: Wikipedia, the Free Encyclopedia
13. Ommatidium: Online Plain Text English Dictionary
14. ommatidium: Webster's Revised Unabridged, 1913 Edition
15. ommatidium: Rhymezone
16. Ommatidium: AllWords.com Multi-Lingual Dictionary
17. ommatidium: FreeDictionary.org
18. ommatidium: Mnemonic Dictionary
19. ommatidium: TheFreeDictionary.com

Computing (1 matching dictionary)

20. ommatidium: Encyclopedia

Medicine (2 matching dictionaries)

21. online medical dictionary (No longer online)
22. ommatidium: Medical dictionary

Science (2 matching dictionaries)

23. DRAGONFLY TERMS (No longer online)
24. Glossary of Entomology (No longer online)

(Note: See ommatidia as well.)

Definitions from Wiktionary (ommatidium) ▸ noun:  (zoology) One of the conical substructures which make up the eyes of invertebrates with compound eyes. Similar: ommatophore, rhabdom, retinophora, cormidium, facet, otocyst, entomere, corneule, mastidion, ocelloid, more... ▸ Words similar to ommatidium ▸ Usage examples for ommatidium ▸ Idioms related to ommatidium ▸ Wikipedia articles (New!) ▸ Popular adjectives describing ommatidium ▸ Words that often appear near ommatidium ▸ Rhymes of ommatidium ▸ Invented words related to ommatidium