Solutions Classification has 12 entries with similar clues

• 3-letter words
• aboBlood classification system
• 5-letter words
• dwarfPluto's classification
• 6-letter words
• octaneGasoline classification
• 7-letter words
• x-ratedOld classification for adult films
• kingdomMajor category of biological classification
• 8-letter words
• nosologyBranch of medicine dealing with the classification of diseases
• taxonomyClassification of living organisms
• 9-letter words
• phoneticsThe study and classification of speech sounds
• libellousDefamatory Aussie demand for classification possibly picked up
• 11-letter words
• call-numberClassification of book in library
• systematicsClassification of living organisms
• 39-letter words
• isbn-international-standard-book-numberA number assigned to a newly published book in keeping with an international book classification system