What is the meaning of ?

The hiragana syllable (ga). Its equivalent in katakana is (ga).

indicates the subject of a verb

but

used to introduce a new topic into the discussion

possessive used to connect nouns, most often seen in place names as ; 's

used after interjected nouns to express contempt

sentence ending particle that indicates emphasis or a question

genitive case marker

  1. Indicates possession: of, -'s

    Indicates possession: of, -'s

    nominative case marker

    1. Indicates the subject of a sentence.

      Indicates the subject of a sentence.

      particle indicating purpose/intent; for; to

      final interrogative particle, similar to a question mark ("?"). Appear only in wh-questions,but followed by やー can be used in other interrogations.

      Source: wiktionary.org