Progressive Video Scans (sometimes referred to as noninterlaced scans) is
a display standard that renders all of the vertical lines of resolution in a video
picture at one time. The format utilizes the faster processing speeds of newer
television systems to render a smoother, yet more detailed and filmlike image,
addressing problems inherent in the older interlaced scan format.

Progressive scanning is commonly used in Blu-ray Discs and in a very few DVD
home video products.

Progressive video scanning is preferred over interlaced scanning. Many current
HD systems (disc players and HD monitors) are capable of converting an older
interlaced signal into a progressive signal (commonly known as line doubling).
We heartily recommend line doubling interlaced DVDs of silent films to create a
more filmlike picture.

More details on progressive video scans may be found on Wikipedia.