Explanation:

- Option:1, which meaning: This is the incorrect segment. The phrasing is awkward. It should be "whose meaning" to correctly indicate possession related to the words.

- Option:2, In this novel: This is grammatically correct. It sets the context of where the words were found.

- Option:3, do not know: This is grammatically correct. It clearly states the uncertainty or lack of knowledge about the meanings.

- Option:4, came across: This is grammatically correct. It expresses the encounter or discovery of the words.