5
votes
2answers
661 views

Why some abbreviations ended with a period, but some not?

I have just bought an Oxford Advanced Learner's Dictionary. This is it's first page showing some abbreviations used in the dictionary. My question is: why some abbreviations ended with a period ...
19
votes
5answers
1k views

Is “iff” considered a real word or just an abbreviation?

I wonder if "iff" is considered a real word (as LEO says) or is it just an abbreviation (as in Wiktionary)?