I am studying vocabulary and I came across the word 然る, either read as さる or しかる (usually written in Kana) and means "A Particular/A Certain" noun. However, there was only one example sentence on there and it wasn't marked as a Common Word, which seems to be a red flag for me in terms of learning the correct vocabulary.
How can I use さる／しかる to express "a particular/a certain" thing? Secondly, is there a better or more natural way to express this phrase?
In order to graduate, you must take a certain class.