What is the meaning of ‘_’?

Encloses a quotation in some languages.

Encloses a quotation, title, ironic comment (scare quotes), nickname, gloss, or the mention of a word (e.g. ‘cheese’ derives from Old English ċīese.).

Encloses an embedded (inner) quotation. The outer quotation is enclosed with “ ”.

Encloses an embedded (inner) quotation.

Encloses an embedded (inner) quotation.

Encloses a doubly embedded quotation.

Encloses a word or expression that is being used in its conceptual meaning or as a definition of another

Encloses an embedded (inner) quotation further inside an already embedded (inner) quotation

Source: wiktionary.org