Definition of countable in US English:

countable

• 1Able to be counted.

• ‘After irradiation, the cells were left for 2 weeks under standard conditions to allow the formation of countable colonies.’
• ‘The world, Heidegger says, is not the mere collection of the countable or uncountable, familiar and unfamiliar things that are at hand.’
• ‘Mathematicians divide infinite sets into two categories, countable and uncountable sets.’
• ‘In the central aspects of explaining the ideas on countable numbers, Aczel does an excellent job, while in peripheral ideas such as explaining the Reimann sphere he does displays a less then exemplary effort.’
• ‘The friends I made with this group are not countable.’
• ‘Of course, if there were no infinite sets then there would be no infinite numbers, countable or uncountable, and so an Aristotelian would not accept the result of this proof as a fact.’
• ‘A full hierarchical perspective suggests a continuum of variation rather than a countable number of objects.’
• ‘I haven't met personally one except I knew there was one or two students at the university and I heard from people saying that there are a countable number of Jewish families still living in Baghdad.’
• ‘By molecules, we generally mean assemblies of a discrete, countable number of atoms.’
• ‘In order to cast a countable vote, a voter must read and follow a set of rudimentary instructions.’
• ‘The difference is, when they do so online, it is countable, transcribable, and therefore more readily part of the political battle and stories thereof.’
• ‘The plates were incubated until the colonies were easily countable.’
• ‘In truth, I imagine my real audience figure only just reaches the maximum number countable using my fingers… on just one hand.’
• ‘Thus, 100 countable individuals was a targeted minimum that was easily surpassed in many samples but not achieved in others.’
• ‘We could add any individual real number to the set of rational numbers and still have a countable collection, just as we may be able to prove individual problems from a non-algorithmic class of problems.’
• ‘Chocolates in a box are countable - two chocolates, a few chocolates, many chocolates, but who's counting?’
• ‘At night the stars were so close it was like a Hollywood set; more bright lights than humanly countable.’
• ‘The concept of reasoning is a key component of activities that capture children's interest-for example, as they interact with countable objects during the acquisition of math skills.’
• ‘As might be expected Cantor went on to find other kinds of infinities that were not countable by the rules he had established.’
• ‘I remain hopeful that, in the din created by the current climate of pre-determined goals, products, standards, and countable outcomes, we will be able to hear.’
1. 1.1Grammar (of a noun) that can form a plural or be used with the indefinite article.
‘‘carton’ and ‘refrigerator’ are countable nouns’

countable

/ˈkaʊn(t)əb(ə)l//ˈkoun(t)əb(ə)l/