The full, formal name should be used on first reference: Tau Kappa Epsilon. A member is a member, never a brother or sister. In reference to a fraternity’s or sorority’s building, the word “house” should be capitalized when it follows the name of the organization: Tau Kappa Epsilon House; fraternity house.
On Second Reference
Abbreviations are acceptable on second reference, but avoid nicknames such as Tri-Delts.