Any kind of sexual interaction with a non-mahram is prohibited, Islamically immoral, and a major sin. There is what we call Zina of the limbs, where one commits Zina with their eyes, by unlawful looking, or Zina by their hands, by unlawful touching, and so on.
May Allah ta'ala protects us all from such.
That being said, jurisprudentially the technical meaning of "Zina" is unlawful sexual intercourse.
And Allah knows best.