When musicians
collaborate on tracks and instead of saying featuring they'd rather use the short terminology "x". This is traditionally used to represent the group of artists as an equal
collaboration; their verses shouldn't be seen as a "feature" but rather the
second half of the song. "Featuring" however is traditionally used to indicate another artist's addition to the main artist's song, hence the use of the term featuring. Nowadays the traditional uses for these terminologies are recreational.