Definition of aggies:
(n) :
(US, informal) An agricultural school, such as one of the state land-grant colleges.
(n) :
(US, informal) A student or alumnus of such a school.
(n) :
(informal) Marble or a marble made of agate, or one that looks as if it were made of agate.
(n) :
(US) An agricultural school, such as one of the state land-grant colleges esp. one with the phrase "Agricultural & Mechanical" in its name
(n) :
(US) A student or alumnus of such a school esp. a student or alumnus of Texas A&M University
(n) :
A diminutive of the female given names Agnes or Agatha.