Idiom: Rule InCheck definitions of...ruleinMeanings By analogy with rule out. How to pronounce "rule in":AU Your browser does not support the audio element. To consider (something) as a possible option among others.A-Z Proximitiesrubber roomruby slippersruck uprue the dayruffle someone's feathers rule in rule of thumbrule OKrule outrule the dayrule the roostSimilar Idiomsas a rulebright-line rulegolden ruleground rulerule of thumbrule inrule OKrule outrule the dayrule the roostrule the schoolrun the rule overtwo-second rulework to ruleSimilar Phrasesalgorithmic rulebest evidence ruleboard rulecarpenter's ruleexclusionary rulefoot rulehearsay rulemajority rulenaegele's ruleplumb rulegag rulegolden rulegrammatical ruleground ruleheuristic rulehome rulerule of lawwork to ruleworking rulelinguistic rule