The phrase "principal purposes" is a correct and usable part of a sentence in written English.
This phrase can be used to refer to the most important reasons behind an action or situation. For example: "The principal purposes of the meeting were to present new strategies and review existing ones."
There are two principal purposes for conducting functional measurements.
Hostility to immigration and Islam are the principal purposes of radical rightwingers in western Europe today.
But set taxes too high, fear campaigners, and you leave the illegal market in place, which destroys one of the principal purposes of legalisation in the first place.
And they returned time and again to the issue of integrity, until one of Barbara Bush's principal purposes came into focus: She was out here to remind voters of an administration without the stain of sexual scandal and to vouch for the character of the Republican presidential nominee.
"Our hope – we are not there yet – is that Senator Corker and I would introduce a managers' amendment that would incorporate certain agreed changes that would make this bill, I hope, accomplish its two principal purposes but without the language that could be offensive to the president and the strength of his negotiations," added Cardin.
The principal purposes of this offering are to increase our public float and financial flexibility.
Today a new wave of fortification is coming, and once again its principal purpose is marketing.
The principal purpose of a mammogram is not simply to prevent death.
The principal purpose of the League is to award & record the master points earned by its sixty-thousand members.
"The principal purpose of trademark law is first to protect consumers and then to protect brand owners," he added.
He did not mention that "their identity and their mission" — their principal purpose, their raison d'être — is often religious proselytization.
