night school; evening school; evening class
Refers to schooling or classes held in the evening, often for people who work during the day. Common in phrases such as 夜学に通う.
He works during the day and attends night school.
I studied English and bookkeeping at evening classes.
night study; studying at night
Use for the activity of studying at night rather than attending an evening school. This sense is less common in modern everyday speech, where 夜に勉強する is usually more direct.
For the week before the exam, he studied hard at night.
He attends night school while working.
She is studying bookkeeping at night school.
He graduated from night school and got a job.