Initialism

An initialism is a word made from the first letters of each word in a phrase. Unlike acronyms, initialisms cannot be spoken as words: they are spoken letter by letter. Examples of initialisms are:

• DVD - Digital Versatile Disc
• CD - Compact Disc
• ATM - Automated (or Automatic) Teller Machine
• BRB - Be Right Back
• NMHU - Not Much Here, You?
• GTG/G2G - Got To Go
• JW - Just Wondering
• JK - Just Kidding
• OK - Okay, "orl korrekt", misspelling of "all correct".

Other websites

• Abbreviations vs. acronyms vs. initialisms
• Origin of the word "OK"
• [https://www.abbreviations.com/ Abbreviations.com, a website full of millions of acronyms!