noun
Arabia
Refers to the Arabian Peninsula or the historical/cultural region of Arabia.
アラビア半島は石油が豊富です。
The Arabian Peninsula is rich in oil.
アラビア語を勉強しています。
I am studying Arabic.
Search-only kanji form; not in common use.
アラブ is often used attributively (e.g., アラブ首長国連邦) or to refer to Arab people/culture, while アラビア is more geographical/historical.
From English 'Arabia' or Portuguese 'Arábia', ultimately from Latin 'Arabia'.