The correct answer is the abbreviation of the word Featuring. In music, it means chorus or cooperation, that is, two people complete a song together. Usually what comes after Ft is for singing or music arrangement, which is different from &. The abbreviation of Featuring can also be written as "Feat".

For example, Pussycat Dolls Ft Busta Rhymes -- Don't Cha

Santana feat Michelle Branch - Game of Love