The phrase "a principal element of" is correct and usable in written English.
It can be used to describe something that is a key or essential part of a larger concept or system.
Example: "Trust is a principal element of effective communication in any relationship."
Alternatives: "a key component of" or "a fundamental aspect of".
It is a principal element of computer-integrated manufacturing, particularly for controlling the operation of machine tools.
These ambitions are important because American military officials say a principal element of any Western exit strategy from Afghanistan will be to create competent national security forces.
The bill, which would replace many benefits -- including free medicine and public transportation and subsidized electricity -- with monthly cash payments, is a principal element of President Vladimir V. Putin's proposed social reforms.
He helped pioneer what became a principal element of the Giuliani administration's crime strategy: arresting people for lesser offenses, like turnstile jumping, and then tying them to more serious ones.
A principal element of ALE is the rezone phase in which a "rezoned" grid is created that is adapted to the fluid motion.
The second video, titled "Journey," outlines a principal element of the campaign: Nikon is giving people "with something to say," as an announcer describes it, "a better camera to say it with" (a Nikon D750 D.S.L.R ., and their photographs will be available on a special website, iamgenerationimage.com.com
A principal element in the creation of the new European cities, the reader discovers, was the construction of sewage and waste disposal systems essential to the health of the populace.
Communication competence "has been cited consistently as a principal element or dimension"[ 1] of quality within the profession of medicine.
Juhayman was from the influential Otaybi tribe from the Nejd, which had led and been a principal element in the original Ikhwan of the 1920s.
What Roscoe had that the others lacked was a self-critical wit and an intelligence that Henry James said was the principal element of any serious novel's center of consciousness.
The principal element of this proposed legislation establishment of a centrally coordinated militia system was rejected by Congress in the Militia Act of 1792.
