What is the meaning of か?

The hiragana syllable か (ka). Its equivalent in katakana is カ (ka). It is the sixth syllable in the gojūon order; its position is か行あ段 (ka-gyō a-dan, “row ka, section a”).

interrogative or rhetorical question particle, similar to a question mark ("?").

indefinite particle; "some-"

カ, ヵ: Used to mark uncertainty in non-conversation factual statements, such as data or proofreading

disjunctive particle; "or"

whether (or not)

indication of doubt

very

forms 形容動詞 (keiyō dōshi, “-na adjectives”) from stems, indicating the state or feeling of an object

Source: wiktionary.org