prin·ci·pal
ˈprin(t)-s(ə-)pəl 
-sə-bəl
1
: most important, consequential, or influential : chief
the principal ingredient
the region's principal city
2
: of, relating to, or constituting principal or a principal (see principal entry 2)
Principle vs. Principal: Usage Guide
Evidence of confusion between principle and principal can be found even in publications overseen by professional editors. To keep these words straight, remember that principle functions only as a noun, and in its most common uses refers to a basic rule or law, as in
a guiding principle
or
a matter of principle.
If you are looking for an adjective form of this word, you must use principled, as in
taking a principled stand.
Principal functions as both a noun and an adjective. The noun has various meanings referring to someone with controlling authority
the school principal
or in a leading position
the ballet's two principals
, but also has meanings relating to finance, law, and architecture. As an adjective, principal typically means "most important," as in
the principal reason.
prin·ci·pal
ˈprin(t)-s(ə-)pəl
-sə-bəl
1
: a person who has controlling authority or is in a leading position: such as
a
: a chief or head man or woman
b
: the chief executive officer of an educational institution
c
: one who engages another to act as an agent subject to general control and instruction
specifically
: the person from whom an agent's authority derives
d
: the chief or an actual participant in a crime
e
: the person primarily or ultimately liable on a legal obligation
f
: a leading performer : star
2
b
: the construction that gives shape and strength to a roof and is usually one of several trusses
broadly
: the most important member of a piece of framing
Examples of principal in a Sentence
Adjective
If any suspect that Griswold was exaggerating, they should reflect on the fact that the principal Supreme Court case justifying the invocation of the national security privilege was based on a governmental lie.
—
Garry Wills, New York Review of Books, 12 Feb. 2009
Following the agreement, the four principal tobacco companies—Philip Morris, R. J. Reynolds, Brown & Williamson, and Lorillard—raised their prices more than 45 cents per pack. The costs of the settlement, as predicted, were passed on to consumers.
—Allan M. Brandt, The Cigarette Century, 2007
Their principal industry was the manufacture, in a long, low, mostly-wooden, two-story factory, of cold cream.
—Frederick Busch, Too Late American Boyhood Blues, 1984
Vegetables are the principal ingredients in this soup.
She is the principal cellist of the orchestra.
Noun
the new high school principal
One of the principals in the assassination plot has been arrested.
Garry Wills, New York Review of Books, 12 Feb. 2009
Following the agreement, the four principal tobacco companies—Philip Morris, R. J. Reynolds, Brown & Williamson, and Lorillard—raised their prices more than 45 cents per pack. The costs of the settlement, as predicted, were passed on to consumers.
—Allan M. Brandt, The Cigarette Century, 2007
Their principal industry was the manufacture, in a long, low, mostly-wooden, two-story factory, of cold cream.
—Frederick Busch, Too Late American Boyhood Blues, 1984
Vegetables are the principal ingredients in this soup.
She is the principal cellist of the orchestra.
Noun
the new high school principal
One of the principals in the assassination plot has been arrested.
Recent Examples on the Web
Evelyn Cheng, CNBC, 24 Apr. 2025
The organization plans to spend $2 million in the coming weeks to focus petitions, phone banks, social media and radio ads on six GOP lawmakers across the country, telling them that their constituents do not support cuts to the principal federal health program for the poor and disabled.
—James Rainey, Los Angeles Times, 24 Apr. 2025
Sergei Klebnikov, Forbes.com, 25 Apr. 2025
That includes the mortgage principal and interest, private mortgage insurance, homeowners insurance, property taxes and other monthly expenses.
—Kelsey Neubauer, CNBC, 24 Apr. 2025
See All Example Sentences for principal
Examples are automatically compiled from online sources to
show current usage.
Read More
Opinions expressed in the examples do not represent those of Merriam-Webster or its editors.
Send us feedback.
Adjective
Yue Su is principal economist, China, at The Economist Intelligence Unit.
—Evelyn Cheng, CNBC, 24 Apr. 2025
The organization plans to spend $2 million in the coming weeks to focus petitions, phone banks, social media and radio ads on six GOP lawmakers across the country, telling them that their constituents do not support cuts to the principal federal health program for the poor and disabled.
—James Rainey, Los Angeles Times, 24 Apr. 2025
Noun
If the index stays above a set barrier—commonly 60-75% of its initial value—the investor gets their principal back, possibly with a coupon.
—Sergei Klebnikov, Forbes.com, 25 Apr. 2025
That includes the mortgage principal and interest, private mortgage insurance, homeowners insurance, property taxes and other monthly expenses.
—Kelsey Neubauer, CNBC, 24 Apr. 2025
See All Example Sentences for principal
Cite this Entry
“Principal.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/principal. Accessed 3 May. 2025.
Copy CitationKids Definition
principal
1 of 2 adjective
prin·ci·pal
ˈprin(t)-s(ə-)pəl
-sə-bəl
: most important : chief
the principal ingredient of the stew
principal
2 of 2 noun1
a
: a leading or most important person
b
: the head of a school
2
: a sum of money that is placed to earn interest, is owed as a debt, or is used as a fund
Legal Definition
principal
1 of 2 adjective
prin·ci·pal
ˈprin-sə-pəl
1
: being the main or most important, consequential, or influential
their principal place of business
the principal obligor
2
: of, relating to, or constituting principal or a principal
the principal amount of the loan
principal
2 of 2 noun1
: a participant in an action or transaction especially having control or authority
the principals of a business
: as
a
: one who engages another to act for him or her subject to his or her general control or instruction : one from whom an agent derives authority to act compare fiduciary
b
: one who commits a crime or instigates, encourages, or assists another to commit it especially when constructively or actually present see also accessory sense 1
—
principal in the first degree
: a principal under common law who intentionally commits and is actually or constructively present at the commission of a crime
—
principal in the second degree
: a principal under common law who aids, encourages, or commands another to commit a crime and is actually or constructively present when it is committed
c
: the person primarily liable on a legal obligation or one who will ultimately bear the burden because of a duty to indemnify another as distinguished from one (as an endorser, surety, or guarantor) who is secondarily liable
2
: a capital sum earning interest, due as a debt, or used as a fund
shall receive the income from the trust until age 18, and thereafter the principal
payments shall be applied first to interest and then to principal
also
: the main body of an estate, devise, or bequest
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