Through meaning

so as to continue in time towards the completion of a process, period, etc.

Ex. "she's just started a tour that will keep her busy right through to June"

Other meanings, from one side to the other / from beginning to end / during an entire period

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

"she walked through the doorway into the living room"

Synonymous:- 

between

past

by

down

along

across

by way of

via

throughout