Hi Corina,
The ladies are right when they don't say the word "frat"...it has a bit of a negative connotation to it and harkens back to Animal House type of images. Use the full word "fraternity".
Also, I wanted to point out that many NPC groups are referred to as "fraternities", even though their membership is women.
For example, Alpha Xi Delta is Alpha Xi Delta
Fraternity, Chi Omega is Chi Omega
Fraternity, but Gamma Phi Beta is Gamma Phi Beta
Sorority. If you and the ladies of NBO can be careful to use the correct terminolgy, it will be that much more impressive to the Officers of the NPC groups when you meet them; it will demonstate that you know your stuff and are sincere about affiliating with an NPC. And why are these "sororities" called fraternities, you ask? Here is the explanation:
At the time of the founding of most of the older women's fraternities, the Greek derivative phratres of phratria, meaning tribes or groups of people with similar interests and backgrounds, was the basis for the title, fraternity. No doubt, because the women's organizations were modeled in many ways after the older men's groups, the women simply used the title fraternity, too.
I also wanted to mention that many people do use the layman's term "actives" to refer to collegiate members.
In the eyes of NPC groups, this is considered
incorrect . Instead use
"collegians" to refer to collegiate members. So a sorority or a [women's] fraternity is comprised of "collegians" and "alumnae". I don't think it hurts to adopt the official Panhellenic terminology right away....
Who is a Fraternity and who is a Sorority?
Here are all the NPC groups:
No, I am not saying you should memorize all 26, but it *is* good to memorize the 4 who ARE interested in colonizing at UCSC. If you ever forget, you can check back here or look at their homepage.
Alpha Chi Omega
Fraternity
Alpha Delta Pi
Sorority -this was kindly pointed out to me by an ADPi member! Thank you!

Alpha Epsilon Phi
Sorority
Alpha Gamma Delta
Fraternity
Alpha Omicron Pi
Fraternity
Alpha Phi
Fraternity
Alpha Sigma Alpha
Sorority
Alpha Sigma Tau
Sorority
Alpha Xi Delta
Fraternity
Chi Omega
Fraternity
Delta Delta Delta
Fraternity
Delta Gamma
Fraternity
Delta Phi Epsilon
Sorority
Delta Zeta
Sorority
Gamma Phi Beta
Sorority
Kappa Alpha Theta
Fraternity
Kappa Delta
Sorority
Kappa Kappa Gamma
Fraternity
Phi Mu
Fraternity
Phi Sigma Sigma
Fraternity
Pi Beta Phi
Fraternity
Sigma Delta Tau
Fraternity-now confirmed
Sigma Kappa
Sorority
Sigma Sigma Sigma
Sorority
Theta Phi Alpha
Fraternity
Zeta Tau Alpha
Fraternity
Also, I wanted to point out that the NPC Recruitment Terminolgy can be found
here. All NPC groups have unanimously adopted this terminology (even though it is a DG webpage). When you are conversing with the ladies of the prospective groups, definitely use the official NPC terminology, it will sound more professional, more classy and will be more impressive in general.
I think you already know to use the word "recruitment" instead of "rush", so you are off to a good start. Good Luck!