noun which may take the genitive case particle 'no', na-adjective, noun
facing each other; opposite; across from
Describes two things or people positioned directly opposite one another. Often used as a noun or with の/な to modify another noun.
私たちは相向かいの席に座った。
We sat in seats facing each other.
相向かいの家は空き家だ。
The house across the street is vacant.
向かい means 'opposite' or 'across from' in a general sense, while 相向かい emphasizes a mutual, face-to-face arrangement.
Compound of 相 (あい, mutual) and 向かい (むかい, facing). The exact historical derivation is uncertain, but the word transparently means 'facing each other'.