a round, hard-fleshed watermelon, Citrullus lanatus citroides, used candied or pickled.
Origin of citron melon
An Americanism dating back to 1800–10
Also called citron.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
Examples from the Web for citron melon
Cream-tartar biscuit, and some cold bread, and some preserved plums; or was it citron-melon she meant to have?Old Friends and New|Sarah Orne Jewett
Sarah Ellen noticed with great gratification that her hostess had put on two of the best tea-cups and some citron-melon preserves.A Country Doctor and Selected Stories and Sketches|Sarah Orne Jewett