place of study; school
A somewhat formal or literary term for a place where learning or scholarly work is conducted. Not the most common everyday word for 'school' (which is 学校), but used in historical or institutional contexts.
An old place of study remains in this town.
He uses part of his house as a study.
塾 is a cram school or private tutoring academy, usually for exam preparation. 学問所 is broader and can refer to any place of scholarly pursuit, not necessarily a commercial school.
Compound of 学問 (がくもん, 'learning, scholarship') and 所 (しょ/じょ, 'place'). The reading じょ is a common rendaku form of 所 when used as a suffix.