When my chapter was a local sorority, we used the big sister/little sister terminology. You found out who your big was on the same day as pledging. (We were a small sorority, so all the pledges had met all the sisters and vice versa during rush, and that was enough conversation time for us to be paired up.)
When we became part of AEPhi, we were told that it was entirely up to us what terminology to use, except that we could NOT use big/little or mother/daughter because it implied that the big was "superior" to the little/new member.
We chose the following:
- Alpha sister: Usually whoever preffed the new member. Gives her little gifts for the first week or so of the NM period.
- Epsilon sister: Usually someone the NM doesn't know as well. Gives her little gifts for the next week or so.
- Phi sister: Equivalent to the big sister. Gives her the $$$ gifts like lettered sweatshirts etc.
Informally, we still used the terms big/little, though (shhh

)