Principal Meaning: First in Rank, First in Line

Principal meaning in its main uses

1. Adjective, main: first in importance. "Rice is the principal crop in the region." "Her principal concern is safety."
2. Noun, head of a school or college: the person who leads it. This is the usual word in the US and India; in the UK, head teacher is more common for schools, while some colleges still have a principal.
3. Noun, money: the original sum borrowed, lent or invested, not counting interest or returns.
4. Noun, in law and business: the person on whose behalf an agent acts, or a main owner or partner in a firm. In criminal law, a principal is a person directly responsible for a crime, as opposed to someone who helped.
5. Noun, in the arts: a leading performer, such as a principal dancer or the principal cellist of an orchestra.

Principal or principle?

These two sound the same but mean different things:

Memory tricks: the principal of a school is your pal, and the principal reason is the main one (both have an a). A principle is a rule. If you can swap in main or head, write principal. If you can swap in rule or belief, write principle.

Principal in sentences

• The principal announced that school would close early because of the storm warning.
• Tourism is the principal source of income for the island.
• After five years, I had repaid about half of the principal on my car loan.
• The agent signed the lease on behalf of her principal, a company based abroad.
• She became principal flute in the city orchestra at just twenty six.

Principal in loans, with numbers

Imagine borrowing 10,000 dollars for a car at 8 percent yearly interest. Your principal is the 10,000 dollars. Interest is the extra you pay for borrowing it. Each monthly payment, or EMI as it is called in India, is split into two parts: some goes to interest and some reduces the principal.

Early in the loan most of each payment covers interest, because interest is charged on a large remaining principal. As the principal falls, more of each payment goes toward it. Paying extra toward principal, when a lender allows it, can shorten the loan and lower total interest. The same idea appears in a mortgage, a bond and an annuity.

Where principal comes from

Principal reached English in the Middle Ages through Old French from Latin principalis, meaning first or chief. That comes from princeps, first or leading person, which also gave us prince. The money sense, the first or original sum before interest, and the sense of a school head both grew from this idea of being first. Principle comes from a related Latin word, principium, a beginning or foundation, which explains why the two look and sound so similar.

Common phrases with principal

• principal amount: the base sum of a loan or deposit.
• principal investigator: the lead scientist on a research project.
• principal place of business: a company's main office, often named in contracts.
• vice principal: the deputy head of a school.
• principal photography: the main filming stage of a movie.

The adverb principally means mainly: "The app is used principally by students." Words for leadership roles and job titles, such as designation, are on related pages, while other tricky pairs appear across our everyday vocabulary pages.