From Longman Dictionary of Contemporary Englishcountablecount‧a‧ble /ˈkaʊntəbəl/ adjective SLGa countable noun has both a singular and a plural form. In this dictionary countable nouns are marked [C] → count noun opp uncountableExamples from the Corpus

countable• For larger systems the bundles of energy were too numerous to be countable.• It may be remarked that the computable numbers, on the other hand, are countable.• We have now seen that the integers are countable, and so also are all the fractions.• We have seen that the number of objects is actually countable in each case.• Since the Turing machines are countable, it must certainly be the case that the computable real numbers are countable.• The Church is made up of countable people and there is nothing particularly spiritual in not counting them.• These terms should strictly only be used for the natural numbers or for other countable sets.