2. Adverb. (mathematics) In a way that can be put into one-to-one correspondence with the natural numbers or any subset thereof. ¹
¹ Source: wiktionary.com
Definition of Countably
Lexicographical Neighbors of Countably
Literary usage of Countably
Below you will find example usage of this term as found in modern and/or classical literature:
1. The Works of William Robertson: To which is Prefixed an Account of His Life by William Robertson, Alexander Stewart (1820)
"Upon this the French and English BOOK ambassadors (for Henry had been drawn unac- w ", countably to concur with Francis in these strange 1537. propositions) ..."