ISO
ISO
To save others time, here's the ISO-8601 document which is apparently being referenced: https://dgn.isolutions.iso.org/obp/ui#iso:std:iso:8601:-1:ed...
"decade" is defined in 3.1.2.22:
decade time scale unit (3.1.1.7) of 10 calendar years (3.1.2.21), beginning with a year whose year number is divisible without remainder by ten Note 1 to entry: Decade is also used to refer to an arbitrary duration (3.1.1.8) of 10 years, however decade is not used as such in this document.
Yes, yes, all of the adjectival disclaimers were used to try to align the discussion directly to how words are used "in [that] document." While the document is highly important, there are many technical contexts in which it is completely appropriate to talk about decades without the slightest consideration of how the same term might be used therein.