altered; altering
ˈȯl-t(ə-)riŋ 
1
: to make different without changing into something else
an event that altered the course of history
: to become different
customs that alter with the times
Synonyms
Examples of alter in a Sentence
Alcohol can alter a person's mood.
He altered his will to leave everything to his sister.
This one small event altered the course of history.
The place has altered in the 10 years since I left.
I'll need to have the dress altered before the wedding.
Recent Examples on the Web
The latter type of metamorphosis creates issues that can’t be easily altered, for instance, shortening a now too-long coat that no longer drapes over a gut.
—
Eric Twardzik, Robb Report, 16 Feb. 2025
The courts also found that the government had altered documents to support their arguments before the Supreme Court as part of justifying the roundup and imprisonment of Japanese Americans.
—James M. Purcell, The Mercury News, 15 Feb. 2025
But researchers are still trying to understand exactly how the fungus alters and affects the brains of spiders to control them.
—Ashley Strickland, CNN, 15 Feb. 2025
Some early movers include: Reddit shares plunged almost 8% after the social media company's number of unique global daily active users, or those who visited the website at least once in a day, missed Wall Street estimates following Google altering its search algorithm.
—Medora Lee, USA TODAY, 14 Feb. 2025
See all Example Sentences for alter 
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Eric Twardzik, Robb Report, 16 Feb. 2025
The courts also found that the government had altered documents to support their arguments before the Supreme Court as part of justifying the roundup and imprisonment of Japanese Americans.
—James M. Purcell, The Mercury News, 15 Feb. 2025
But researchers are still trying to understand exactly how the fungus alters and affects the brains of spiders to control them.
—Ashley Strickland, CNN, 15 Feb. 2025
Some early movers include: Reddit shares plunged almost 8% after the social media company's number of unique global daily active users, or those who visited the website at least once in a day, missed Wall Street estimates following Google altering its search algorithm.
—Medora Lee, USA TODAY, 14 Feb. 2025
See all Example Sentences for alter
Dictionary Entries Near alter
Cite this Entry
“Alter.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/alter. Accessed 19 Feb. 2025.
Copy CitationKids Definition
alter
verb
al·ter
ˈȯl-tər
Etymology
Middle English alteren "to make different," from Latin alterare (same meaning), from Latin alter "other (of two)" — related to adulterate
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