One-way means allowing travel in a single direction only. A one-way street, a one-way ticket, one-way glass.
The ticket sense came first, in 1906, and the street sense followed in 1914. A one-way ticket carries a note of finality in fiction that a return does not, which is why it appears in so many songs.
1adjectiveone-wayAllowing travel in a single direction only — streets or tickets.
“You can't turn left here; it's a one-way street.”
one-way is a quality.
One plus way, first recorded of tickets in 1906 and of streets in 1914.
From one + way. First attested in 1906 in reference to one-way tickets; 1914 in reference to one-way streets; 1940 in reference to one-way mirrors.
Etymology from Wiktionary, CC BY-SA