What is the meaning of ?

The hiragana syllable (o). Its equivalent in katakana is (o). It is the forty-seventh syllable in the gojūon order; its position is (wa-gyō o-dan, row wa, section o).

A case particle.

  1. An accusative case particle: a grammatical marker following the direct object of a verb.

    An accusative case particle: a grammatical marker following the direct object of a verb.

    away from, off

    along, following a specified route, track, orbit, etc.

    A conjunctive particle, usually following the rentaikei of classical inflectible words.

    1. Resultative conjunction: expresses reason or cause.
    2. Contrastive conjunction.

    Resultative conjunction: expresses reason or cause.

    Contrastive conjunction.

    An interjectory particle, expressing sigh or emphasis.

    Source: wiktionary.org