Japanese: 生徒

A student of a particular person.

It is a title that needs to be acknowledged by, i.e., the teacher (Sensei).

Following a couple of lessons with someone does generally not qualify you as a Seito of this person.

See also: Biginaa, Shirouto, Nawa Yaru Hito, Seito, Kohai, Senpai, Menkyo, Deshi.