RATE RULE this is not an expression with meanings, but rather two similar words that in some situations, and with much generosity, could be considered synonymous, and were as such but without the corresponding separating comma, so probably the search bot found it as an undefined phrase and here we are facing a "phrase" that is actually spam So to review in RAE the second meaning of TASA and the fifth meanings and the locutions company rule, rule of three, rule of three composed of RULE if you really have any doubts, guys. Example: the rate of children born with blue eyes is similar to that predicted by the rules of inheritance defined by Mendel, and therefore well called Mendel's Laws.
