Answer: aps

AnswerCrossword Clue
APSBiblical twelve: Abbr.
APSH.S. courses for college credit
APSColl.-level classes
APSExams for college cred.
APSCalendar mos.: var.
APSCollege-level H.S. courses
APSH.S. courses for coll. credit
APSSST's, e.g.
APSStamp collectors' org.
APSRm.-and-meals systems
APSPhilatelic group.
APSStamp collectors' group: Abbr.
APSH.S. VIPs
APSCollege-level H.S. classes
APSStampers' org.
APSTests for college credit, briefly
APSMay exams for H.S. students
APSCourses for coll. credit