Through Liam and Jasper's journey for the truth and Ted Pryce being beckoned by Domino, The Royals gave its "Loyals" answers to what exactly Domino is on the Dec. 27 episode of Season 2. On The Royals, Domino is a person — well, actually a nickname for King Simon's true love, Dominique Stewart. When Simon and Dominique were young, they wanted to marry, but Dominique died in a horse riding accident and a family feud was born.
After Liam saw a blonde girl at his and Eleanor's birthday party, he remembered her being there when he was kidnapped in Season 1 and received the Domino necklace. He teamed up with Jasper to figure out her identity and while it wasn't safe for them to talk, she gave him a piece of paper with the name "Dominique Stewart" on it. That clue led Liam to visit his father's old servant to get answers and Simon's old comrade explained that Dominique was Simon's love and after a horse jumping contest, she died, which led to the king marrying Helena.
Pryce's interactions in "Taint Not Thy Mind, nor Let Thy Soul Contrive Against Thy Mother" with the mysterious Domino man confirmed the identity and meaning behind Domino. Turns out, that mystery man is Dominique's brother and his nickname for her when she was young was "Domino." He believes that Helena's family is responsible for killing his sister so that Helena could end up being queen.
Back to the blonde girl, she is the Domino man's daughter and the niece of the now-dead Dominique. She was named after her aunt and has been raised to seek revenge on the royal family for killing her aunt. She explained that her father wants Liam's family to fall down — one by one — like dominoes. Yet, she approached Liam because she realized maybe he isn't as evil as she has been brought up to thought. But was she really sincere in the information she gave Liam?
When the young Dominique got home after giving Liam (some) of the answers he was searching for, her father knew that she was with the prince. So had Dominique been purposefully sent to Liam as a way to get closer to the royal family? If so, then while Dominique may have spoken the truth about what Domino is, that doesn't mean she should be trusted.
Dominique seemed hesitant when speaking with her vengeful father and I'm prone to believe that her intentions with Liam were honest. Even if Dominique may think that Liam descends from killers, that doesn't mean she thinks he should be killed. But regardless of her motives, this won't be the last the Loyals see of Dominique in Season 2 of The Royals. And although the revelation has led to more questions, at least fans finally know what — and who — Domino stands for now.