molly
noun
any of certain livebearing freshwater fishes of the genus Poecilia (formerlyMollienisia ), popular in home aquariums.
molly
1 American
[mol-ee]
/ ˈmɒl i /
noun
-
mollies
plural
molly
2
American
[mol-ee]
/ ˈmɒl i /
noun
-
mollies
plural
molly
3
American
[mol-ee]
/ ˈmɒl i /
molly
4
American
[mol-ee myool]
/ ˈmɒl i ˌmjul /
noun
Molly
5
American
[mol-ee]
/ ˈmɒl i /
noun
molly
1
British
/ ˈmɒlɪ /
noun
molly
2
British
/ ˈmɒlɪ /
noun
Other Word Forms
Noun Inflected Forms
Etymology
Origin of molly1
First recorded in 1930–35; shortened from New Latin Mollienisia, named after French statesman Count F. N. Mollien (1758–1850); see -ia
Origin of molly2
First recorded in 1930–35; formerly a trademark
Origin of molly3
First recorded in 1975–80; origin uncertain; perhaps a shortening of black molly, a tropical aquarium fish supposedly resembling the black pills; other authorities suggest it is a shortening and alteration of molecule ( def. )
Origin of molly4
First recorded in 1980–85; generic use of the proper name
Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
See Examples For:
Organisms like the salmon and molly that can tolerate a relatively wide range of salinity are referred to as euryhaline organisms.
From Textbooks ● Jun. 9, 2022
In the sulfur-infused ponds of Tabasco state in Mexico lives a tiny silver slip of a fish, the sulphur molly.
From Seattle Times ● Dec. 22, 2021
The waves also appeared to make it more difficult for kiskadees to successfully nab a molly, and both birds often changed perches in response to the waves, possibly searching for a different angle of attack.
From Scientific American ● Dec. 22, 2021
The Amazon molly evolved about 280,000 years ago from the interbreeding of two other species of fish, the Atlantic molly and the sailfin molly.
From New York Times ● Feb. 26, 2021
A few days after molly arrives at Vivian’s, she texts Ralph to let him know where she is.
From "Orphan Train" by Christina Baker Kline
A second wave of AI matchmaking startups—including Amata, Known and the forthcoming venture from Hinge founder Justin McLeod—is taking aim at customer swipe fatigue, Molly Reinmann writes.
From The Wall Street Journal ● Aug. 4, 2026
A test of your news knowledge: Recap the events of this week by going head-to-head with Slate staff writer Molly Olmstead in our news quiz.
From Slate ● Jul. 24, 2026
Sharing more from their marriage ceremony, Molly posted a photo to her Instagram story of her hand on top of Tom's.
From BBC ● Jul. 23, 2026
Earlier this year, Tom and Molly took over hosting duties of the NearlyWeds podcast from radio presenters and reality stars Jamie Laing and Sophie Habboo.
From BBC ● Jul. 23, 2026
A second door opened into another dimly lit room, and “mourners”—actors without masks who Molly assumed were Anat’s classmates—filed in, a few carrying tiny plates with rugelach, others wailing perhaps too theatrically into handkerchiefs.
From "Night Owls" by A.R. Vishny
She just had some questions how to treat ich, an illness that had wiped out her mollies.
From New York Times ● Mar. 17, 2023
They quickly noticed that they were not the only ones looking at the mollies.
From Scientific American ● Dec. 22, 2021
The sulphur mollies seem to be one of the rare cases in which the benefits of a synchronized behavior can be teased out.
From Seattle Times ● Dec. 22, 2021
It would be noteworthy if the sulfur mollies are indeed sending a message to their predators through a collective effort, the researchers say, because the fish are not closely related to each other.
From Science Magazine ● Dec. 22, 2021
“I turn my back for five minutes and everybody lets my black mollies die off. I should’ve taken them to college with me. I knew that.”
From "Franny and Zooey" by J. D. Salinger
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
