I was reading in Mignon Fogerty's Quickanddirtytips_When you need periods after abbreviations about the guidelines she gives covering the use of periods at the end of abbreviations ... when you should do so; but now I am wondering whether these guidelines change when abbreviating the plural form of the word?
Word: Extension US Abbreviation: Ext. British Abbreviation: Ext.
Word: Extensions US Abbreviation: Exts. British Abbreviation: Exts. or Exts
Now using the guidelines from that page, US English always uses a period at the end of abbreviations so it would be
Exts.; however British English denotes that you only use a period at the end when the last letter of abbreviation doesn't match the last letter of the full word.
With that in mind then that is why with the non-plurlal version you end up using
Ext., but the question now is, do we keep following this tandard and just append an
s to the end for
Exts. or do we know say the
s at the end of the abbreviation now matches the
s at the end of the full word and instead use