DIVA'S FORTE is a term used to describe the special talent or skill of a female singer. The two crossword solutions ARIA (4 letters) and TRILL (5 letters) are both vocal techniques used by singers. An ARIA is a type of song with a solo vocal part, usually accompanied by an orchestra. A TRILL is a rapid alternation between two notes, often used to add ornamentation to a melody. Together, these two techniques form the basis of a diva's forte.