These are some I used for a bulletin board for my fish this year. It's not a complete list, but it should get you started.
Aggie Spirit: undefinable, yet an awesome force that overtakes students, former students, and friends of Texas A&M University
Bad Bull: anything that does not promote the Aggie Spirit.
CT: member of the Corps of Cadets
Dead Elephant: any senior student during the spring semester
Frog: cadet who joins the Corps after he/she starts school
Gig ‘Em: Pinky Downs, class of 1906 and a member of the Board of Regents from 1923 to 1933, is credited with the Gig ‘Em hand sign. At the 1930 Yell Practice before the TCU football game, Downs shouted out, "What are we going to do to those Horned Frogs?" Answering his own question, he replied, “Gig ‘Em, Aggies!” while making a fist with his thumb extended. A “gig” is a spear-like tool used for hunting frogs. The gesture became known as the first hand sign of The Southwest Conference. It is now used as a sign of encouragement and approval.
Good Bull: anything that promotes the Aggie Spirit
Howdy: If you walk across the Texas A&M University campus, you are sure to be greeted with the word "Howdy" several times. The word "Howdy" has come to symbolize the friendliness of the A&M campus.
Humping it: position taken by an Aggie when giving a yell. To do this, put your hands on your knees and bend forward at the waist.
Non-reg: an undergraduate student who is not a member of the Corps of Cadets
Ol’ Army: like it “used to be” at A&M
Redpots: students responsible for coordinating the building of Bonfire. There are 16 (eight seniors, eight juniors) who wear red hardhats, or “pots”
tsip: student at t.u.
t.u.: Aggie term for the University of Texas, that other school in Austin
12th Man: Aggies not actively engaged in an athletic event but who support the team
Whoop: an Aggie expression of approval. Only juniors and seniors have earned the privilege of whooping
Wildcat: another Aggie expression of approval; each academic class has its own wildcat
Yell: commonly known at other universities as a cheer
Yell leader: one who leads yells and yell practice
Yell practice: spirit session held regularly during the football season. Before home games, it is held at midnight at Kyle Field.
Zip: any senior