diamond
n.— «First sergeants are required to be at least a master sergeant to wear a diamond on their sleeve, which is why they are sometimes referred to as “diamonds.” However, technical sergeants may be selected to hold the additional-duty first sergeant position, which involves many of the same responsibilities as a “diamond.”» —“‘Diamonds’ help raise Edwards’ bar” by Mike Young Edwards Air Force Base (California) Nov. 30, 2007. (source: Double-Tongued Dictionary)
Further reading
Diamond dust, tapioca snow, and sugar icebergs — a 1955 glossary of arctic and subarctic terms describes the environment in ways that sound poetic. And a mom says her son is dating someone who’s non-binary. She supports their relationship, but...
John in Tucson, Arizona, remembers his grandfather from Sharon, Vermont, saying possessives such as hisn, hern, yourn, and ourn, as in Those cattle are hisn or That house is hern. These archaic forms go back to Middle English, shaped by analogy with...