The phrase "a sort of rule" is correct and usable in written English.
It can be used to describe something that is not a strict rule but rather a guideline or general principle.
Example: "In our organization, we follow a sort of rule that encourages open communication among team members."
Alternatives: "a kind of guideline" or "a type of principle".
And if it's not dark energy, are there revisions needed in Einstein's theory of general relativity"—a sort of rule book for spacetime and other fundamental physics to best explain this acceleration?
"I never do housework, it's a sort of rule of mine, I really don't like it," she says.
But as that would be limiting, I have a sort of rule that says death by natural causes is O.K. -- we do 'Bohème' -- but not death by violence.
"Fair use," a judicially-created doctrine, is a sort of "rule of reason" applied by the courts as a defense to copyright infringement when the accused infringing acts are deemed to be outside the legitimate scope of protection afforded copyright owners under 17 U.S.C. § 1.
In this, he reminds me of Matisse, whose late work is his least ponderous: the scissor cuts of paper, often in leaflike shapes, are also a sort of rule-based art.
For the most part, that strategy has become a sort of Rules of Acquisition for today's startups.
To give you a sort of rough rule of thumb, if you look in Europe or the U.S., it's closer to 20%.
The unmarried lovers have a sort of semiserious rule about straying with other partners: it's O.K. if either one is beyond a radius of 200 miles.
"We had a sort of unwritten rule that whoever was walking in or out of the showroom would check the typewriter," Mr. Spachholz said.
I was actually taught this when I was about 15, as a sort of "magic rule" with no real explanation, but also as a challenge, since the teacher said there was an explanation but it was too difficult.
Each poem in this substantial collection is just 15 lines long (though they are divided up in different ways), as if the poet were following a sort of spiritual rule to sharpen the senses through variant repetition.
