What is the meaning of ?

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

with

and

a particle following a phrase or clause describing the detail, content or manner of the action, similar to a complement.

if

when

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

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

Source: wiktionary.org