"Los actores principales"
Translation:The main actors
principle: Noun A fundamental truth or proposition that serves as the foundation for a system of belief or behavior or for a chain of reasoning. A rule or belief governing one's personal behavior.
Adjective First in order of importance; main. Noun The person with the highest authority or most important position in an organization.
Principal is the correct spelling in this case.
cam2644. Actually, no. The "principal actors", referring to a leading role, is a common phrase. "Principle actor" is not, and does not make sense..
Although, an actor might be "principled" (having ethical principles)-- but that is something different.
This is only partly correct (Your first sentence is correct but this is not the only use of "principal"; your second sentence is incorrect.). See this link for a few examples: http://grammarist.com/spelling/principle-principal/ or this link for more info: http://www.quickanddirtytips.com/education/grammar/principal-versus-principle?page=all
Principle is only a noun and refers to a natural, moral, legal rule or standard. Principal is a noun and adjective with specialized meanings in finance and law but most commonly used to refer to someone in a position of authority or high prominence. (Oxford English Dictionary)