[georgerr]

What does Refractor mean on a card?

[jplarson]

Refractor is a printing technology developed by Topps (Panini uses a similar printing technique they call Prizm) which shows up as a rainbow effect on the card. Sometimes it can be hard to see so you may need to move it around in the light a bit to see the rainbow. Refractors printed in the 1990s are the easiest to see in my opinion.

Topps used to print "refractor" on the back as a means to help collectors differentiate them from regular cards.

[kerryandbeth]

It means "that card is worth collecting" to me! They look really nice in displays.

[savagenate]

Chase the rainbow! Collect all the colored refractors and it's a fun way to collect a player!

[djohn]

Topps came up with the name "refracto" as a parallel version of it's high end Finest product when it was first released in 1993. The word refractor stems from the term refraction. Refraction is simply the bending of light. However refraction through a prism separates the different colors of light and produces a rainbow, similar to light passing through raindrops. Topps used this same physical phenomena to create a layer on the surface of the card that refracts light when it hits the card surface, thus causing a rainbow effect on the surface of the card.
The word refractor is reserved for Topps Chrome and Finest products, however that includes some lesser known sets like Stadium Club Chrome and Topps Mystery Finest. Some people have a hard time recognizing refractors, and for some releases Topps actually printed the word "refractor" on the back of the card (typically around the location of the card number). Now, there are several different color refractors, but the color merely relates to the background or border color of the card, along with using the refraction technology.
When Panini introduced their Prizm line of cards they used the same technology to make "Prizm" parallels. To make things a bit more confusing, when initially released the parallels were simply called Prizms, so you had cards known as Prizm Prizms. In more recent years, the basic Prizm parallel is now known as a Silver Prizm.