What is the meaning of が?

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

1. indicates the subject of a verb

   indicates the subject of a verb

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

   1. used to introduce a new topic of discussion by way of a short preface or explanation

      used to introduce a new topic of discussion by way of a short preface or explanation

      but

      no matter; regardless of

      1. used in anapodota to indirectly express one's own wishes, requesting the listener to oblige one somehow

         used in anapodota to indirectly express one's own wishes, requesting the listener to oblige one somehow

         used in anapodota to express wishes one thinks are unlikely (or even impossible) to be fulfilled; it would be nice if ...; if only ...

         expresses anger, dissatisfaction, annoyance, etc.

         used after interjected nouns to express contempt

         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