Is “Rule” a Scrabble word?
Yes
RULE
Valid in at least one Scrabble dictionary
Valid in these dictionaries
SOWPODS / CSW
Scrabble UK & International
TWL / NWL
Scrabble North America
Large English Dictionary
General English word list
Meaning of Rule
/ɹuːl/
noun
1.A regulation, law, guideline.
“All participants must adhere to the rules.”
2.A ruler; device for measuring, a straightedge, a measure.
3.A straight line (continuous mark, as made by a pen or the like), especially one lying across a paper as a guide for writing.