Question

Why is abbreviated such a long word ​

Answer 1

Answer:

Because it started with a fairly short word, brevio, Latin for "short". Then a prefix was added, ab-, to indicate "motion towards" (cognate to "at"). Then the suffix -ated was added to indicate the verb in the past participle form.

Dictionaries: making observational humor jokes less funny since 1662.

Answer 2

Because brevis, meaning short, was extended to add additional meaning, just like short becomes shortened whilst getting longer. More meaning = longer word. Abbreviation is also not, itself, an abbreviation.