For questions about the shortened forms of words or phrases.
Abbreviations are shortened forms of words, or phrases.
In strict analysis, the difference between abbreviation, and contraction is the following:
An abbreviation may be made by omitting certain portions from the interior or by cutting off a part
A contraction of a word is made by omitting certain letters or syllables and bringing together the first and last letters or elements
A contraction is an abbreviation, but an abbreviation is not necessarily a contraction.