Ag·​ro·​bac·​te·​ri·​um | \ ¦a-grō-ˌbak-ˈtir-ē-əm \

Definition of Agrobacterium

: a genus of small usually gram-negative and motile bacterial rods (family Rhizobiaceae) including soil forms that vigorously reduce nitrates and several pathogens of cultivated plants that typically cause galls on stems — compare crown gall

Love words?

You must — there are over 200,000 words in our free online dictionary, but you are looking for one that’s only in the Merriam-Webster Unabridged Dictionary.

Start your free trial today and get unlimited access to America's largest dictionary, with:

  • More than 250,000 words that aren't in our free dictionary
  • Expanded definitions, etymologies, and usage notes
  • Advanced search features
  • Ad free!

First Known Use of Agrobacterium

1942, in the meaning defined above

History and Etymology for Agrobacterium

New Latin, from agro- + bacterium

Keep scrolling for more

Learn More about Agrobacterium

Time Traveler for Agrobacterium

Time Traveler

The first known use of Agrobacterium was in 1942

See more words from the same year

Statistics for Agrobacterium

Cite this Entry

“Agrobacterium.” Dictionary, Merriam-Webster, Accessed 8 Jul. 2020.

Comments on Agrobacterium

What made you want to look up Agrobacterium? Please tell us where you read or heard it (including the quote, if possible).


See Definitions and Examples »

Get Word of the Day daily email!

Test Your Vocabulary

A More Exception(al) Quiz

  • hot dog  hot dog  hot dog  hot dog cat
  • Which of the following words is not a synonym for ‘a young person’?
Spell It

Can you spell these 10 commonly misspelled words?


Test Your Knowledge - and learn some interesting things along the way.

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!