My daughter is a full time student. She took a summer code close to home last year related to her full time course of study at the college she's attending.
The college defines what is full time. I doubt one course would qualify.
Whether or not a student is considered a full-time student is determined by the school. Schools may have different criteria for summer versus fall and winter classes. If you received a 1098-T from the school where the summer course was taken, is box 8 checked. Box 8 indicates that the student is enrolled at least half-time, which is one of the eligibility requirements for the education tax credit. AOTC FAQs
Probably not, but it doesn't matter. Being full time (FT) for the other two terms qualifies her as FT for the dependent test. She only needs to be half time, or more, for the course to count for the tuition credit. One class, for the short simmer period, is usually half time.