prin- +

(Latin: first, chief)

Directly related to the prim- family unit of words.

prince (s) (noun), princes (pl)
1. A male member of a royal family other than the monarch, especially a son of the monarch.
2. A man who is a ruler of a principality.
3. A hereditary male ruler; a king.
4. A nobleman of varying status or rank.
5. An outstanding man, especially in a particular group or class.
6. Etymology: from Latin princeps, principis, "first, chief"; literally, "that takes first", from primus, "first" + root of capere, "to take".
princely (adjective), more princely, most princely
1. Relating to, belonging to, or suitable for a prince.
2. Of or relating to a prince; royal.
3. Generous as an amount of money, or requiring the expenditure of large sums of money: "They donated a princely sum to the charity."
princess (s) (noun), princesses (pl)
A female member of a royal family other than the queen; especially, the daughter of a sovereign.
principal (s) (noun), principals (pl)
1. A chief or head.
2. The head or director of a school or; especially, in England, a college.
3. A person who takes a leading part in any activity, as a play; a chief actor or performer.
4. The first player of a division of instruments in an orchestra (except the leader of the first violins).
5. Something of primary or chief importance.

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principal, principle quiz

Principal-Principle Words, Quiz or at this principal-principle category link.

principality (s) (noun), principalities (pl)
1. A territory ruled by a prince or princess.
2. The position or jurisdiction of a prince.
3. Etymology: from Late Latin principalitatem, principalitas, from principalis, "first in importance"; from princeps, "first, chief".
1. For the most part, chiefly.
2. Above all; especially.
3. Almost entirely; mainly.
1. First or highest in ranks, importance, values, etc.; chiefs.
2. Of the natures of, or constituting principals; such as, significant principals were invested in the company.
principle (s) (noun), principles (pl)
1. An accepted or professed rule of action or conduct: "She was a person of good moral principles."
2. A fundamental, primary, or general law or truth from which others are derived; such as, the principles of physics.
3. A fundamental doctrine or tenet.
4. Principles, a personal or specific basis of conduct or management: "He was known as someone who always stirved to adhere to his principles."
5. Guiding sense of the requirements and obligations of right conduct; a person of principle.
6. A rule or law exemplified in natural phenomena, the construction or operation of a machine, the working of a system, or the like.
7. Etymology: from Latin principium, principia, "a beginning, first part"; from princeps, "first, chief".

Learn how to distinguish between principle and principal.

principled (adjective), more principled, most principled
Conveying honesty and responsibility about what someone does and how he or she treats other people.
unprincipled (adjective), more unprincipled, most unprincipled
Lacking principles or moral scruples; unscrupulous: unprincipled behavior.

You may find further details as to the differences between Principal and Principle with mnemonic guidance for clarifying the confusions that often arise with these two words.