I'm talking mostly in popular music / rock / etc. One prominent example of what I'm referring to is the start of Queen's Bohemian Rhapsody (pretty much up to the "I'm just a poor boy ... "; notice that at that point, even though there are multiple voices, that's a completely different thing: Freddie Mercury sings the melody, and several voices do a backing "oooooohhhh.... aaaaahhhh...." (well, or whatever they may be saying, if there's supposed to be lyrics in those back vocals)
In Spanish, we use (at least informally) the same word for "chorus", typically phrased as "in chorus" (as in, at the start of Bohemian Rhapsody, they sing in chorus). I guess being used to that usage, I'm eagerly trying to find an equivalent word in English. And yes, the chorus (now referring to the English meaning of the word chorus in the context of pop/rock music) typically (perhaps most of the time, although not always) is sung in that mode (that word that I'm looking for).
- The term is very specific; polyphony or polyphonic is not specific enough (virtually 100% of popular music has at least a good fraction of the song that is polyphonic, if I understand correctly the term).
- I would assume that "choral" is also not specific enough, although certainly, what I'm describing is an instance of a melody, not the chorus of a song, being sung by a vocal ensemble — in the context of pop/rock or other styles of popular music, where we are not talking about "choral music".
- The term is not restricted to multiple voices in unison — in that starting bit in Bohemian Rhapsody, at least to my ear, the different voices are not always singing the same note (perhaps we could see it as a sequence of chords; each syllable in "is this the real life" is made by a chord where each note of the chord is sung by a different vocalist).