os·​si·​fy | \ ˈä-sə-ˌfī How to pronounce ossify (audio) \
ossified; ossifying

Definition of ossify

intransitive verb

1 : to change into bone The cartilages ossified with age.
2 : to become hardened or conventional and opposed to change so easy for the mind to ossify and generous ideals to end in stale platitudes— John Buchan

transitive verb

1 : to change (a material, such as cartilage) into bone ossified tendons of muscle
2 : to make rigidly conventional and opposed to change ossified institutions ossified ideologies

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Did You Know?

The skeletons of mammals originate as soft cartilage that gradually transforms into hard bone (in humans, the process begins in the womb and continues until late adolescence). English speakers have referred to this bone-building process as ossification since the late 17th century, and the verb ossify appeared at roughly the same time. English speakers had begun to use both ossification and ossify for more figurative types of hardening (such as that of the heart, mind, or soul) by the 19th century. Both words descend from the Latin root os, meaning "bone." Os is also an English word that appears in scientific contexts as a synonym of bone, and the Latin term is an ancestor of the word osseous, which means "consisting of or resembling bone."

What is the difference between ossify and calcify?

Medically speaking, ossify refers to the process by which bone forms, or by which tissue (usually cartilage) changes into bone. Ossification is a natural process that starts in utero and which comprises several different steps—one of which is the deposit of calcium salts, also known as calcification. Calcify, however, only refers to the deposit of calcium salts in soft tissue and is not synonymous with ossify. Ossification creates bone tissue, which is more than simply a deposit of calcium salts.

Both ossify and calcify have gained more general uses as well. Calcify refers to hardening, to becoming inflexible and unable to change:

What were once upstart revisionist currents calcified into self-regarding academic sub-specialties, sponsoring plenty of analysis but little fundamental debate.
— Sean Wilentz, The New Republic, 2 July 2001

Ossify refers to becoming inflexible, conventional, and resistant to change:

For these writers, the ossified ideologies of the world, imbedded in the communal imagination, block vision, and as artists they respond not by criticism from without but by confrontation from within.
—Robert Coover, The New York Times Book Review, 18 Mar. 1984

While ossify generally has a slightly more disparaging connotation to it than calcify does in general uses, our evidence shows that the two words are beginning to merge semantically.

Examples of ossify in a Sentence

The cartilage will ossify, becoming bone. a disease that ossifies the joints

Recent Examples on the Web

Unlike many people of their generation, Helen and Brice have not ossified in their emeritus years. Douglas Friedman, Town & Country, "Inside Artist Brice Marden and His Wife Helen's Bohemian Caribbean Haven," 22 Oct. 2018 The riots spread throughout Athens, then beyond into Thessaloniki and elsewhere in Europe, drawing many of the battle lines that would ossify once the Greek crisis erupted the following year. Charly Wilder, New York Times, "Athens, Rising," 18 June 2018 Jako, dark-eyed glassine baby sardines, bodies ossified, taste like shattered deep-sea bacon. Ligaya Mishan, New York Times, "Rice Balls, Subtle and Showy Alike, at Omusubi Gonbei," 12 Apr. 2018 Meanwhile, the connection between our government and our largest companies has ossified. Nick Bilton, The Hive, "“Threats,” “Ultimatums,” and “Espionage”: Inside Silicon Valley’s Spy Wars," 13 Apr. 2018 Sure, some of the show’s humor has ossified; parts have grown creaky and potentially perilous with age. Richard Lawson, vanityfair.com, "Will & Grace Review: A Surprisingly Welcome, Wistful Return," 26 Sep. 2017 Instead of ossifying into an autocratic force, Kerala’s communists embraced electoral politics and since 1957 have been routinely voted into power. Rick Noack, Washington Post, "One of the few places where a communist can still dream, and 4 other global stories," 2 Nov. 2017 Nor is North Korea as ossified as outsiders might imagine. Brook Larmer, New York Times, "North Korea Is No Longer the Hermit Kingdom — but How Long Will China Be Its Lifeline?," 18 Oct. 2017 In recent years, his vernacular rhythm has ossified into a dull pastiche of itself. Richard Lawson, HWD, "Wonder Wheel Review: A Pretty Melodrama with a Woody Allen Problem," 13 Oct. 2017

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'ossify.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of ossify

1699, in the meaning defined at transitive sense 1

History and Etymology for ossify

Latin oss-, os + English -ify

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The first known use of ossify was in 1699

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English Language Learners Definition of ossify

formal + disapproving : to become or to cause something to become unable to change
technical : to become or to cause something to become hard like bone


os·​si·​fy | \ ˈäs-ə-ˌfī How to pronounce ossify (audio) \
ossified; ossifying

Medical Definition of ossify

intransitive verb

: to form or be transformed into bone cartilage ossified postnatally

transitive verb

: to change (as cartilage) into bone osteoblasts ossify the tissue

More from Merriam-Webster on ossify

Rhyming Dictionary: Words that rhyme with ossify

Comments on ossify

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


not constant or steady

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