We found 21 dictionaries that define the word thingamabob:

General (17 matching dictionaries)

1. thingamabob: Merriam-Webster
2. thingamabob: Oxford Learner's Dictionaries
3. thingamabob: American Heritage Dictionary of the English Language
4. thingamabob: Collins English Dictionary
5. thingamabob: Vocabulary.com
6. thingamabob: Wordnik
7. thingamabob: Cambridge Advanced Learner's Dictionary
8. thingamabob: Wiktionary
9. thingamabob: Webster's New World College Dictionary, 4th Ed.
10. thingamabob: The Wordsmyth English Dictionary-Thesaurus
11. thingamabob: Infoplease Dictionary
12. thingamabob: Dictionary.com
13. ThingamaBob, Thingamabob: Wikipedia, the Free Encyclopedia
14. thingamabob: Rhymezone
15. thingamabob: FreeDictionary.org
16. thingamabob: Mnemonic Dictionary
17. thingamabob: TheFreeDictionary.com

Business (1 matching dictionary)

18. Construction Term Glossary (No longer online)

Computing (1 matching dictionary)

19. thingamabob: Encyclopedia

Slang (2 matching dictionaries)

20. thingamabob: Green’s Dictionary of Slang
21. thingamabob: Urban Dictionary

(Note: See thingamabobs as well.)

Definitions from Wiktionary (thingamabob) ▸ noun:  (slang) A thing or person whose actual name is unknown or forgotten. Similar: thingumabob, thingmajig, doodad, thingamajig, thingumajig, thingummy, dohickey, dojigger, thingmabob, doohickey, more... ▸ Words similar to thingamabob ▸ Usage examples for thingamabob ▸ Idioms related to thingamabob ▸ Wikipedia articles (New!) ▸ Popular adjectives describing thingamabob ▸ Words that often appear near thingamabob ▸ Rhymes of thingamabob ▸ Invented words related to thingamabob