With your answer to my question I learned an expression of 'mihi nomen est..' for 'my name is...'. And you said 'nomen meum est..' is wrong.
But I saw 'Joannes est nomen eius.' for 'John is his name.' As per your answer it should be 'ei nomen est Joannes.' not 'eius'. Both possible in this case?
And also what is 'Your name is Marcus.' in Latin?
And Both sentences below are the same in meaning? 'What's your name?
Quid est nomen tibi? (quid is pronoun?)
Quod nomen est tibi? (quod is adjective?)
please note that “Joannes est nomen eius” for “John is his name”, as it appears in the official motto for the island of Puerto Rico whose formal name is "San Juan Bautista de Puerto Rico” with reference to the name that Christopher Columbus had originally given the island, honoring John the Baptist, is late Latin, not classical Latin, where with "nomen est", and similar expressions, the name is often put in the Dative as a kind of apposition with the person, though the Nominative is also common, so that we can say e.g. either “Mihi nomen est Marcus" (nominative agreeing with “nomen”) or “Mihi nomen est Marco" (dative agreeing with “mihi”).
Therefore in classical Latin “Your name is Marcus” translates as “Tibi nomen est Marcus” as well as “Tibi nomen est Marco”.
As for “What's your name?”, it corresponds to “Quod nomen est tibi?” where “quod” is an adjective and in classical Latin we find:”Quis est poeta?” (Who is the poet?) where “quis” is an interrogative pronoun, and :“Qui poeta est?” (What kind of poet is he?) where “qui” is an interrogative adjective.
Anyway, since “quis” is very common also as an adjective, especially with words denoting a person: as, “quis dies fuit?” ( what day was it?), “ quis homo?” ( what man? ), but often “qui homo?” ( what kind of man?), we can say that both “Quid est nomen tibi?” (quid is pronoun?) and “Quod nomen est tibi?” (quod is adjective?) could be used .