dissolve (lap dissolve)

Dissolves are a transitional edit between two scenes, shots, or sequences in which the image of one shot is slowly replaced, blended, or superimposed with a different image. A dissolve, or lap dissolve, is usually done to suggest a passage of time. "Lap dissolve" is shorthand for "over'lap dissolve." Also known as a "soft transition" or "dissolve to." In contrast to "cross-fade."