noun
single application; applying to only one school
Used in the context of school admissions, where a student applies to only one institution, often as a first-choice commitment.
彼は第一志望の大学に単願で出願した。
He applied to his first-choice university as a single application.
単願入試は合格したら必ず入学しなければならない。
If you pass the single-application entrance exam, you must enroll.