round-trip ticket
US /ˈraʊnd.trɪp ˌtɪk.ɪt/
UK /ˈraʊnd.trɪp ˌtɪk.ɪt/

1.
a ticket that allows a person to travel to a place and back again
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I bought a round-trip ticket to New York.
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How much is a round-trip ticket to London?
a ticket that allows a person to travel to a place and back again