A spelling alphabet (also known as a phonetic alphabet or a telephone alphabet) is a set of words which are used to stand for letters of the alphabet; they're typically used when spelling out words over the telephone or in other noisy or low-bandwidth environments.
"Pessimal Spelling Alphabets,"
Word Ways: Vol. 46
, Article 18.
Available at: https://digitalcommons.butler.edu/wordways/vol46/iss2/18