Merriam-Webster Logo
SINCE 1828
Menu
×

An Encyclopædia Britannica Company

See What's Trending Now See More Trending Words

septic tank

noun

Definition of septic tank

:a tank in which the solid matter of continuously flowing sewage is disintegrated by bacteria

See septic tank defined for English-language learners

See septic tank defined for kids

Explore Merriam-Webster

video-title-words-of-the-year-1066
Words of the Year: 1066
image989362072
8 Words for Trickery and Deception
alt-59e8af1b31525
Trending: NY Times: Trump's Call Ignites 'Imbroglio'
one-green-toy-robot-amidst-many-red-toy-robots
The Exceptions Quiz III

First Known Use of septic tank

circa 1902

SEPTIC TANK Defined for English Language Learners

septic tank

noun

Definition of septic tank for English Language Learners

  • : a tank under the ground that holds human waste from toilets

Learn More about septic tank

  1. Britannica.com: Encyclopedia article about septic tank

Seen and Heard

What made you want to look up septic tank? 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

burke

play

to suppress quietly or indirectly

Get Word of the Day daily email!

TRENDING NOW

  1. imbroglio "a public scandal"

  2. spurious of a deceitful nature or quality

  3. righteous We provide an assortment of definitions

  4. Kafkaesque 'A nightmarish quality'

  5. mike "microphone"

SEE ALL

BROWSE DICTIONARY

Test Your Vocabulary

The Exceptions Quiz III

  • one-green-toy-robot-amidst-many-red-toy-robots
  • Which of these words does not mean "nonsense"?
Name That Thing

Test your visual vocabulary with our 10-question challenge!

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

image989362072
8 Words That Put One Over on You

They'll put one over on you

alt-59ee3fc46688e
'Dis': From Early Rap to Academic Journals

The word has quickly taken center stage

alt-59ea52ed7b96f
Learned Fools: On Names for Students

Where did we get 'freshman' and 'sophomore'?

alt-59e900afadac6
The Synonyms 'Discover' and 'Invent'

In the past, you could invent fruit.

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

one-green-toy-robot-amidst-many-red-toy-robots
The Exceptions Quiz III

Which of these things doesn't belong?

Take the quiz
knupfer-painting-solon-before-croesus
Forms of Government Quiz

Name that government! Or something like that.

Take the quiz
Name That Thing
Name That Thing

Test your visual vocabulary with our 10-question challenge!

Take the quiz
SCRABBLE® Sprint
SCRABBLE® Sprint

SCRABBLE® fans, sharpen your skills!

Play the game