To save this word, you'll need to log in.
Definition of acid-free
: not containing acid : having a neutral or alkaline pH
acid-free paper Every evening, trained volunteers will place any personal items or memorabilia left at the replica wall in archival folders or acid-free boxes.— Brian Burnes, Kansas City Star, 22 Sept. 2010
Keep scrolling for more
Comments on acid-free
What made you want to look up acid-free? Please tell us where you read or heard it (including the quote, if possible).
Test Your Vocabulary
Semantic Drift Quiz
- Which of the following was once a synonym for fun?
Can you spell these 10 commonly misspelled words?
TAKE THE QUIZ
Test Your Knowledge - and learn some interesting things along the way.
TAKE THE QUIZLove words? Need even more definitions?
Merriam-Webster unabridgedWords at Play
Ask the Editors
Word Games
- Semantic Drift Quiz
A challenging quiz of changing words.
Take the quiz - A Thanksgiving Word Quiz
We are thankful for obscure words.
Take the quiz - Spell It
Can you spell these 10 commonly misspelled words?
Take the quiz - Dictionary Devil
The dictionary has been scrambled—can you put it back together?
Play the game
Share acid-free
Time Traveler for acid-free
The first known use of acid-free was in 1885
See more words from the same year