vis-a-vis is an expression from the French language and has the meaning of "face to face" or "face to face".
In French, vis-a-vis is a phrase considered synonymous with tête-à-tête, which also expresses the meaning of "face to face", that is, two people or situations that are presented from opposite sides, confronting or comparing.
Etymologically, the term vis was an Old French word meaning "face", which originated from the Latin visum, which means "seen".
In Portuguese, this expression is more common in cultured contexts, not being used in informal conversations, for example.
Vis-à-vis can also be the name of a sofa model, in an "S" shape, in which people are seated facing each other, facilitating conversation between them. In this same context, vis-à-vis is still called a type of carriage where passengers sit in opposite directions, but with their faces turned towards others, stimulating contact between them.
