alum

1 of 3

noun (1)

al·​um ˈa-ləm How to pronounce alum (audio)
1
: a potassium aluminum sulfate KAl(SO4)2·12H2O or an ammonium aluminum sulfate NH4Al(SO4)2·12H2O used especially for its astringent and styptic properties
2
: any of various double salts isomorphous with potassium aluminum sulfate
3

alum

2 of 3

noun (2)

: alumnus, alumna
a Yale alum

alum

3 of 3

abbreviation

Did you know?

Is it acceptable to use alum for alumnus or alumna?

The words that we have used to refer to people who have attended or graduated from a school, college, or university have changed a bit over the past several centuries. Traditionally, the word alumnus has been used to refer to a single male, whereas alumna has been used for a single woman. Initially the plural forms were alumni to refer to multiple men (or multiple men and women) and alumnae for multiple women. A little over a hundred years ago the shortened form of alum began to be used to describe a graduate or past attendee of either gender. Although many people feel that alum is informal, it is in increasing use, and we appear to be moving toward a greater acceptance of the word. The plural of alum is alums.

Examples of alum in a Sentence

Recent Examples on the Web
Noun
The following month, Dancing with the Stars alums — including Maks Chmerkovskiy, Kym Johnson-Herjavec, Tony Dovolani, Karina Smirnoff, Anna Trebunskaya, Edyta Śliwińska, Louis van Amstel and Mark Ballas — and current pros performed a touching dance in honor of Goodman. Carrie Ann Inaba, Peoplemag, 22 Apr. 2024 Pyramid Sculpture Park Home in Hamilton In 1987, Miami University alum Harry T. Wilks purchased land to build his Pyramid House before expanding to what is now Pyramid Hill Sculpture Park and Museum, a three-hundred-acre nonprofit park featuring over 70 outdoor sculptures. Grace Tucker, The Enquirer, 21 Apr. 2024 Continue reading here… ‘TRUE BEAUTY’ - 'American Idol' alum, gospel singer Mandisa dead at 47. Fox News Staff, Fox News, 20 Apr. 2024 In a statement to Billboard, a representative for Grammy-winning Christian contemporary music artist and American Idol alum Mandisa confirmed that the singer passed at age 47 in her home. Kyle Denis, Billboard, 19 Apr. 2024 But Grant Hill, USA Basketball’s managing director, wants to make one thing clear: The Clippers forward and San Diego State alum did not dramatically get the final spot on the roster heading to France this summer. Mark Zeigler, San Diego Union-Tribune, 18 Apr. 2024 When the Giants signed his fellow Titan alum, Davis became expendable. Brian Robin, Orange County Register, 18 Apr. 2024 Bethenny Frankel's miscarriage was a blessing in disguise, according to the reality TV alum. Naledi Ushe, USA TODAY, 17 Apr. 2024 On Wednesday, April 10, the Gossip Girl alum, 36, gushed about Ryan Reynolds’, 47, while sharing the trailer for his upcoming movie IF on her Instagram Stories. Gabrielle Rockson, Peoplemag, 11 Apr. 2024

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'alum.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History

Etymology

Noun (1)

Middle English, from Anglo-French alum, alun, from Latin alumen

Noun (2)

by shortening

First Known Use

Noun (1)

14th century, in the meaning defined at sense 1

Noun (2)

1877, in the meaning defined above

Time Traveler
The first known use of alum was in the 14th century

Dictionary Entries Near alum

Cite this Entry

“Alum.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/alum. Accessed 26 Apr. 2024.

Kids Definition

alum

noun
al·​um
ˈal-əm
1
: either of two colorless crystalline compounds containing aluminum that are used in medicine (as to check local sweating or to stop bleeding)
2

Medical Definition

alum

noun
al·​um ˈal-əm How to pronounce alum (audio)
1
: either of two colorless or white crystalline double sulfates of aluminum used in medicine internally as emetics and locally as astringents and styptics:
a
: one KAl(SO4)2·12H2O that is a sulfate of aluminum and potassium

called also potassium alum

b
: one consisting of an ammonium aluminum sulfate NH4Al(SO4)2·12H2O

called also ammonia alum, ammonium alum

2
: any of various double salts isomorphous with potassium aluminum sulfate

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