http://rd.vernccvbvyi5qhfzyqengccj7lkove6bjot2xhh5kajhwvidqafczrad.onion/define.php?term=an%20abbreviation
.), NYC, pm (or p.m.), U.S. (or US). Practice varies with regard to periods, with current usage increasingly in favor of omitting them, especially when the initialism consists entirely of capital letters. 4 Acronyms are initialisms that have become words in their own right, or similar words formed from parts of several words.