ISO 80000 or IEC 80000, Quantities and units, is an international standard describing the International System of Quantities (ISQ). It was developed and...

by ISO/IEC 80000-3:2007) ISO 31-2: Periodic and related phenomena (replaced by ISO/IEC 80000-3:2007) ISO 31-3: Mechanics (replaced by ISO/IEC 80000-4:2006)...

to space and time. It was superseded in 2006 by ISO 80000-3. Its definitions include: Annex A of ISO 31-1 lists units of space and time based on the foot...

symbols for quantities and units related to mechanics. It is superseded by ISO 80000-4. Its definitions include (note boldfaced symbols mean quantity is a...

from the French "unité astronomique". In the non-normative Annex C to ISO 80000-3:2006 (later withdrawn), the symbol of the astronomical unit was also...

and technology. It was superseded in 2009 by ISO 80000-2:2009 and subsequently revised in 2019 as ISO-80000-2:2019. Its definitions include the following:...

rotating machines. One revolution per minute is equivalent to 1/60 hertz. ISO 80000-3:2019 defines a physical quantity called rotation (or number of revolutions)...

quantities. The system is formally described in a multi-part ISO standard ISO/IEC 80000 (which also defines many other quantities used in science and...

interval [4: ISO 80000-3]. The SI unit of this quantity is thus the reciprocal second (s−1). However, as pointed out in Ref. [4: ISO 80000-3], the designations...

itself is often considered incorrect, with some preferring to use "ky". ISO 80000-3 recommends usage of ka (for kiloannum), which avoids the implicit English...