Question: cd is countable or uncountable?
Answer: (compact disc read-only memory) a CD on which large quantities of information can be stored to be used by a computerFrom Longman Business DictionaryCD-ROM /ˌsiː diː ˈrɒm-ˈrɑːm/ (also CD-Rom) noun [countable, uncountable] compact disc read-only memory; a small disk on which large quantities of information can be stored ...