The term 'disappears gradually' can be described by four different crossword solutions: FADES (5 letters), EVANESCES (9 letters), ERODES (6 letters), and FDST (4 letters). FADES is a verb meaning to become less intense or visible over time. EVANESCES is also a verb, meaning to gradually disappear or become less noticeable. ERODES is a verb meaning to gradually wear away or be destroyed by natural forces such as wind or water. Finally, FDST is an acronym for 'Fade Out Slowly Then, ' which is a technique used in film and television production to slowly transition from one scene to another.