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

a ten-minute drive through the tunnel brought us to the city of Whittier

water was pouring through holes in the roof

continuing in time towards completion of (a process or period)

the goal came midway through the second half

so as to inspect all or part of (a collection, inventory, or publication)

I flipped through the pages

by means of (a process or intermediate stage)

dioxins get into mothers' milk through contaminated food

up to and including (a particular point in an ordered sequence)

they will be in London from March 24 through May 7

expressing movement into one side and out of the other side of an opening, channel, or location

as soon as we opened the gate they came streaming through

I went through to the bedroom to answer the phone

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

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

my partner was genuinely surprised that babies wake up in the night —he thought newborns sleep through

make sure to watch the video all the way through

so as to inspect all or part of a publication or document

she read the letter through carefully

so as to be connected by telephone

she put the call through to a nurse

(with reference to public transport) continuing or valid to the final destination

a through train from London

a through ticket

(of a room) running the whole length of a building

(of a team or competitor) having successfully passed to the next stage of a competition

Swindon Town are through to the third round

having no prospect of any future relationship, dealings, or success

she told him she was through with him

you and I are through