always used before a noun
: most important : chief
Vegetables are the principal ingredients in this soup.
My principal [=main] reason for moving is to have a shorter drive to work.
She is the principal cellist of the orchestra.
plural principals
1
a
US
: the person in charge of a public school
the new high school principal
b
British
: the person in charge of a university or college
2
: an amount of money that is put in a bank or lent to someone and that can earn interest
—usually singular
Our monthly mortgage payment covers the interest on our loan as well as some of the principal.
3
a
: the main performer in a group of performers
The ballet featured the two principals. [=lead dancers]
b
: the most important person in a group
One of the principals in the assassination plot has been arrested.
Cite this Entry
“Principal.” Merriam-Webster.com Simple Definition, Merriam-Webster, https://www.merriam-webster.com/simple/principal. Accessed 16 Apr. 2026.
Copy Citation
