through

Concise Oxford English Dictionary © 2008 Oxford University Press:
through/θruː/

▶preposition & adverb

• 1 moving in one side and out of the other side of (an opening or location).

  ■ so as to make a hole or passage in.

  ■ [prep.] expressing the position or location of something beyond (an opening or an obstacle).

  ■ expressing the extent of changing orientation.

• 2 continuing in time to or towards completion of.

  ■ from beginning to end of (an experience or activity).

• 3 so as to inspect all or part of.

• 4 [prep.] N. Amer. up to and including (a particular point in a sequence): from March 24 through May 7.

• 5 by means of.

• 6 [adv.] so as to be connected by telephone.

▶adjective

• 1 (of public transport or a ticket) continuing or valid to the final destination.

• 2 (of traffic, roads, etc.) passing continuously from one side and out of the other side.

• 3 having successfully passed to the next stage of a competition.

• 4 informal having finished an activity, relationship, etc.: you and I are through.

– phrases
through and through thoroughly or completely.

– origin OE thurh, of Gmc origin.