Cherry and Ruby are two varieties of red fruits. Cherry is a small, round fruit with a smooth, bright red skin and a sweet, juicy flesh. Ruby is a larger, oval-shaped fruit with a deep, dark red skin and a tart, juicy flesh. Both fruits are popular for their sweet-tart flavor and vibrant color. Reds is an appropriate four-letter answer for the crossword clue, as it accurately describes both of these fruits.