What is the meaning of と?

The hiragana syllable と (to). Its equivalent in katakana is ト (to). It is the twentieth syllable in the gojūon order; its position is た行お段 (ta-gyō o-dan, “row ta, section o”).

2. with; marks a companion, partner, etc. that an action is done with

   with; marks a companion, partner, etc. that an action is done with

   can be optionally attached to some adverbs to (slightly) highlight the explanatory nature of the adverb

   marks the result of a transformation; (turn) to, into

   follows a phrase or clause describing the detail, content or manner of an action; commonly used to mark dialogue or thoughts

   when used with the same verb twice, used to mean "every"; constructed using the ren'yōkei first, followed by the rentaikei

   used to join nouns; and

   used to express co-occurrence or causality of events

   1. marks an action, after which something else happens in succession; (soon) upon (doing something), when

      marks an action, after which something else happens in succession; (soon) upon (doing something), when

      marks a condition which, whenever met, causes something to happen; whenever; if

      marks a condition of which one wishes to express a reasonably expectable consequence; if

      marks a short preface to something one is about to say

      short for と金 (tokin): a promoted 歩兵 (fuhyō, “pawn”) that moves like a 金将 (kinshō, “gold general”)

      indicates emphasis or a question

      Source: wiktionary.org