When do you learn....
 

Some GLOs have Greek letters on the new member (pledge) pins. The letters are not the letters on the badge. For example, there's "B" on the PiPhi pledge pin, "Pi Alpha" on the Delta Gamma's, "Beta Upsilon Alpha" on ADPi's, Sigma-within-Delta on KKG's.

Do new members learn what that stands for in the new member ceremony, or is the meaning revealed at initiation?

Fraternally,

AGDAlum
(who can still recite, along with thousands of her sisters, "on a shield parti per pale, or and vert, a fess gules," which is the proper heraldic description of the Alpha Gamma Delta pledge pin)

At Beta we have three stars on our pledge pins and we were told that the meaning would be revealed during initiation.

They did however tell us that the white enamel represented purity, and the gold of the stars the refinement we would be reaching. Probably pretty standard stuff there.

When do you learn...
 

Kappa's learn what the Sigma within the Delta pledge pin means at initiation. I would assume that this is true for other groups as well.

Pi Phis learn about the Beta during the pledging ceremony but it's kind of detailed and I swear you have to hear it for years to remember the meaning!

Not Greek letters... but the AEPhi pledge pin is an adaptation of the crest, without the Greek letters (since only sisters may wear the letters). New members learn part of the crest's symbolism at pinning, and the rest at initiation.

I always thought it odd that a new member would be asked/required to wear a pin with Greek letters or symbols where they have no clue about the meaning.

The D Phi E new member pin is a purple triangle with the gold letters Delta Phi Epsilon. While new members can wear letters, they may not wear the crest. They learn the meaning of the pin through the new member ceremony, but some things are held off on until initiation.