student enrolled from an affiliated lower-level school
Used in educational contexts to refer to a student who entered a school (often a university or high school) from an affiliated institution, as opposed to an external applicant. Common in discussions of school admissions systems.
この大学では、内部生の割合が高い。
At this university, the proportion of students from affiliated schools is high.
内部生と外部生では、入学後の成績に差はほとんどない。
There is almost no difference in academic performance after enrollment between students from affiliated schools and those from outside.
Compound of 内部 (ないぶ, 'internal') and 生 (せい, 'student'). The exact historical derivation is uncertain, but the term follows a common pattern for describing student categories in Japanese education.