The trigger words, translated/subtitled from Russian into English, were:
- Longing
- Rusted
- Seventeen
- Dawn
- Stove
- Nine
- Kind-hearted
- Homecoming
- One
- Freight car
No exact explanation has been given what the words actually reference, but hypnosis typically involves words and phrases in sequences that are unlikely to be randomly said in order.
You would think that "homecoming" is an out-of-universe nod to the upcoming Spider-Man: Homecoming, but the screenwriters dismiss that that connection being made as "fairly accidentally".
Terri Schwartz: There are some very obvious setting up for Spider-Man: Homecoming in this movie, which must have been really exciting for you guys. But maybe it was because the name Spider-Man: Homecoming was just announced right before I saw this movie. The word "homecoming" popped up a couple times in this film...
Stephen McFeely: Fairly Accidentally
Additionally, Bucky fell from a freight car when he was lost and presumed dead. Finally, Bucky was born in 1917 (one, nine, seventeen)