A teaching assistant or teacher's aide (TA) or education assistant (EA) or team teacher (TT) is an individual who assists a teacher with instructional responsibilities. TAs include graduate teaching assistants (GTAs), who are graduate students; undergraduate teaching assistants (UTAs), who are undergraduate students; secondary school TAs, who are either high school students or adults; and elementary school TAs, who are adults (also known as paraprofessional educators or teacher's aides). By definition, TAs assist with classes, but many graduate students serve as the sole instructor for one or more classes each semester as a teaching fellow or graduate student instructor, although in some states, such as Florida, they are called "teaching assistants". Graduate and adult TAs generally have a fixed salary determined by each contract period (usually a semester or an academic year); however, undergraduates and high school students are sometimes unpaid and in the US and other countries with the credit system, receive course credits in return for their assistance. Teaching assistants often help the main teacher by supporting students with learning disabilities, such as ADHD, Autism, or physical disabilities, such as blindness or deafness. Graduate Graduate teaching assistants (often referred to as GTAs or simply TAs) are graduate students employed on a temporary contract by a department at a college or university in teaching-related responsibilities. In New Zealand, Australian, and some Canadian universities, graduate TAs are known as tutors. North American graduate TA positions provide funding for postgraduate research—although the main purpose is to provide teaching support—and it often serves as a first career step for aspiring academics. TA responsibilities vary greatly and may include: tutoring; holding office hours; invigilating tests or exams; and assisting a professor with a large lecture class by teaching students in recitation, laboratory, or discussion sessions. Professors may also use their teaching assistants to help teach discussions during regular class. This gives the graduate student opportunity to use their teaching skills, as many are in pursuit of teaching careers. Some graduate students assist in distance education courses by meeting with the students as professors are not able to. Graduate TAs should not be confused with teaching fellows (TFs) or graduate student instructors (GSIs), who are graduate students who serve as the primary instructors for courses. However, at some universities, such as those in the Florida State University System, there are neither teaching fellows nor graduate student instructors, and "teaching assistant" is the only title