For reference, an associated Policy Note (you don't need to visit this link yet):
Notes
[CONVENTION, NAMING, PATTERN, STYLE, TIP]{RECOMMENDED} Mathematica: The Webel Units` package has Quantity variables for frequently used units using a naming convention 'unit$[Symbol]' or 'unit[DescriptiveName]' or unit[Acronym], each with a corresponding '$unit...' for the units identifier String(s).