Using the word "surgery" as an adjective [closed]

Solution 1:

I am familiar with the noun 'surgery' being used in this sense, but not so much with the adjective, as in 'surgery classes'.

Here is an article (from a US dictionary) that explains the use of the term in British English.

Surgery - The word has a special meaning in British English 16 Jun 2016

...a regular gathering known in Britain as a surgery, which means “a special period of time when people can visit [someone] to ask questions.”

https://www.merriam-webster.com/news-trend-watch/surgery-2016-06-16

I am British and so I'm used to hearing this to mean that people have a time when they can consult with an expert. Originally the expert would have been a medical doctor, but now it can refer to any such meeting. A lecturer can hold a surgery to help students, a member of parliament can hold a surgery to be attended by their constituents, etc.

The meaning has been expanded here: A doctor sees one patient at a time. An MP sees one constituent at a time. Your lecturer seems to use it to refer to meeting more than one student at a time.