Las palabras del día: Principal, príncipe & principio/s

These three terms are also very tricky. I hope this post clarifies.
Principal. Adjective: main. E.g.: Su principal logro hasta el momento, según coinciden en su mayor parte los analistas, es que no se han roto: Their main achievement to date, analysts tend to agree, is that they have not broken down.
Principio/s. Masculine noun, usually in plural: principle/s. E.g.: No confundan los valores ni menosprecien sus principios: Do not mix up your values or betray your principles.
Principio: Masculine noun, usually in singular. Beginning. E.g.: Desde el principio me involucré en muchos negocios: From the beginning I was involved in many businesses.
Príncipe: Male noun. Prince. The female form is princesa. Remember that in the Spanish Monarchy príncipe or princesa is just the heir to the Spanish throne, any other son or daughter of the Spanish king is an infante or infanta, pretty much like the term fils de France.
On another note, the English noun ‘principal’ in Spanish is usually translated as director/a de escuela. dc