Learn the meaning, pronunciation and usage of the preposition through in English. See examples of through in different contexts, such as movement, time, barriers, means and more. As an adjective, through means finished or done. As an adverb it can mean backward and forward, completely, up to and including, or all the way to the end. The preposition through means in and out of. having no interruption, obstruction, or hindrance: a through highway; through ticket. Civil Engineering (of a bridge truss) having a deck or decks within the depth of the structure. Through definition: in at one end, side, or surface and out at the other.. See examples of THROUGH used in a sentence.