Where does “西アジア” come from?

西アジア (Japanese) comes from Japanese アジア, from Chinese 亞細亞, from Latin Āsia, from Ancient Greek Ἀσία, from Mycenaean Greek 𐀀𐀯𐀹𐀊, from Hittite 𒀸𒋗𒉿 — northwest Anatolia.

Ancestry of “西アジア”, step by step

西アジア traces back through two separate lines of ancestry.

via Japanese アジア

Step	Language	Word	Meaning
1	Japanese	アジア	Asia
2	Chinese	亞細亞	—
3	Latin	Āsia	A kind of rye
4	Ancient Greek	Ἀσία	Asia Minor; Asia; Asia
5	Mycenaean Greek	𐀀𐀯𐀹𐀊	an ethnonym for a Lydian; an epithet of the...
6	Hittite	𒀸𒋗𒉿	northwest Anatolia

via Japanese 西

Step	Language	Word	Meaning
1	Japanese	西	west; the West; wind blowing from the west
2	Japanese	し	Conjunctive particle. Follows items in a list of...
3	Middle Chinese	氏	—

Every word from Hittite 𒀸𒋗𒉿 →Every word from Mycenaean Greek 𐀀𐀯𐀹𐀊 →Every word from Ancient Greek Ἀσία →