af·​ter·​treat·​ment | \ ˈaf-tər-ˌtrēt-mənt \

Definition of aftertreatment

: a secondary treatment to which a material (as film or dyed goods) is subjected after the primary treatment is finished

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 aftertreatment

1852, in the meaning defined above

History and Etymology for aftertreatment

after- + treatment

Keep scrolling for more

Learn More about aftertreatment

Time Traveler for aftertreatment

Time Traveler

The first known use of aftertreatment was in 1852

See more words from the same year

Statistics for aftertreatment

Cite this Entry

“Aftertreatment.” The Dictionary, Merriam-Webster Inc., Accessed 17 January 2020.

Comments on aftertreatment

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


a plan in which a last survivor takes all

Get Word of the Day daily email!

Test Your Vocabulary

The Eponym Quiz

  • rubens painting
  • Which is the best synonym of bowdlerize?
Spell It

Can you spell these 10 commonly misspelled words?

Dictionary Devil

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!