Merriam-Webster Logo
SINCE 1828
Menu
×

An Encyclopædia Britannica Company

See What's Trending Now See More Trending Words

brown rat

noun

Definition of brown rat

  1. :  a common domestic rat (Rattus norvegicus) that has been introduced worldwide —called also Norway rat

See brown rat defined for kids

From the M-W Editors

watercolor-squares
We're Down With You Being—or Your Being?—a Square
time-traveler-quiz-which-word-came-first
Time Traveler Quiz: Which Word Came First?
image1489982902
Devilish Words
video-title-words-of-the-year-1066
Words of the Year: 1066

First Known Use of brown rat

1737

Medical Dictionary

brown rat

noun

Medical Definition of brown rat

  1. :  a common domestic rat of the genus Rattus (R. norvegicus) that has been introduced worldwide—called also Norway rat

Learn More about brown rat

  1. See words that rhyme with brown rat Britannica.com: Encyclopedia article about brown rat

Seen and Heard

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

show hide

Love words? Need even more definitions?

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

WORD OF THE DAY

hebetude

play

lethargy or dullness

Get Word of the Day daily email!

TRENDING NOW

  1. Svengali 'A person who manipulates'

  2. syzygy An obscure astronomy term goes mainstream

  3. hegemon "Something having dominant influence over others"

  4. repugnant Trump clarifies his position on racism

  5. white nationalist, white supremacist Trending in 2017

SEE ALL

BROWSE DICTIONARY

brown rat

Test Your Vocabulary

Time Traveler Quiz: Which Word Came First?

  • time-traveler-quiz-which-word-came-first
  • Which came first?
Spell It

Can you spell these 10 commonly misspelled words?

TAKE THE QUIZ
SCRABBLE® Sprint

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

TAKE THE QUIZ

Love words? Need even more definitions?

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

Words at Play

watercolor-squares
We're Down With You Being—or Your Being?—a Square

It's about (you? your?) having your say.

image1489982902
Devilish Words

Don't blame a word use error on the devil.

alt-599492594f435
How 'Wonderful' Lost Its Sense of Wonder

A case of semantic bleaching

dog-covering-face
Don't Let Reading This Be Another 'Coulda' 'Shoulda' 'Woulda'

PSA: They're three separate words.

Ask the Editors

video-title-words-of-the-year-1066
Words of the Year: 1066

Or, Why Pig Meat is Called 'Pork' and Cow Meat is Called 'Beef'

payday
How Often Is 'Biweekly'?

Don't get us started on 'bimonthly'

video-irregardless-grammar-peeve-blend-of-the-synonyms-irrespective-and-regardless
Irregardless

It is in fact a real word (but that doesn't mean you should use it).

video-moose-goose-weird-plurals
Weird Plurals

One goose, two geese. One moose, two... moose. What's up with that?

Word Games

time-traveler-quiz-which-word-came-first
Time Traveler Quiz: Which Word Came First?

Which word entered the English language first?

Take the quiz
name-more-food
Name More Food!

Test your knowledge of food vocabulary!

Take the quiz
Spell It
Spell It

Can you spell these 10 commonly misspelled words?

Take the quiz
SCRABBLE® Sprint
SCRABBLE® Sprint

SCRABBLE® fans, sharpen your skills!

Play the game