[honeychile]

From the open part of Alpha Delta Pi's website:

"A legacy is a sister, daughter, or granddaughter of an initiated member of Alpha Delta Pi. We believe the initiation of these women strengthens family ties, giving the chapter increased support. ADPi members are welcome to introduce a potential member or legacy to a collegiate chapter using our Potential Member and Legacy Forms."
My little sister didn't fill these forms out for her daughters, but I have it on very good authority that several alumnae made sure that their status was known!

While great-granddaughters aren't mentioned, a tie to any Adelphean, Alpha Delta Phi, or Alpha Delta Pi prior to say, 1950, is going to be considered a legacy - especially an Adelphean!