principal

These two words, though they have the same pronunciation, have different meanings and functions. Principle is a noun only, meaning "a basic assumption," "an ethical standard," and "a way of operating or working," as in the principles of a democratic system;a woman of principle;studied the principles of the internal-combustion engine. By contrast, principal, as a noun, means "a school administrator," "an important participant," "a lead performer," and "a monetary amount invested," as in was sent to the principal's office;a principal in an accounting firm;a principal of $500,000. As an adjective it means "primary": our principal [not principle] reason for an appeal.