This word is acceptable for play in the US & UK dictionaries that are being used in the following games:

• Lexulous
• Wordscraper
• Wordosaur

adj. Of, printed, or formatted in capital letters: an uppercase A; uppercase titles.

v. To put (type or text) in uppercase letters.

v. To begin (a word) with an uppercase letter.

adj. written in upper case; capital

n. Alternative spelling of upper case.

n. one of the large alphabetic characters used as the first letter in writing or printing proper names and sometimes for emphasis

adj. relating to capital letters which were kept in the top half of a compositor's type case

"Possibly because it is written entirely in uppercase, which surely means something regarding relative rank and importance."

majuscule    great    capital   

upper    multiport    cease-and-desist    fixed-width    non-free