Template:2022 SI prefixes

and adopted by the in 2022 as an expansion to the  beyond 10±24.

Some popular unofficial terms already in use were, and , but terms beginning with the same letters as existing prefixes were considered undesirable, as were as those beginning with common scientific letters such as  or. Richard J. C. Brown suggested that the new terms begin with and, due to their rarity as unit symbols, and that the trends followed by the other prefixes be continued: that they be based on Latin or Greek; that large prefixes end with  and small prefixes end with ; that they should be in corresponding large and small pairs; and that the first letters of each prefix should be in reverse alphabetical order (as has been the case for the newer prefixes). He therefore suggested and  (evoking  and ), and  and  (evoking  and ), because as 1027 and 1030 when written have nine and ten groups of zeroes, respectively. These were adopted, with changed to.