There isn't a direct, single-word translation of "Emmanuel" into Greek. Emmanuel is a Hebrew name (אֱמָנוּאֵל) meaning "God is with us." To translate it into Greek, you would need to render the meaning, not a direct equivalent. The most accurate translation would be a phrase, such as:
* ὁ Θεὸς μεθ᾿ ἡμῶν (ho Theos meth' hēmōn) - This is a literal translation: "God with us."
Other options that capture the essence, though not a word-for-word translation, might include phrases emphasizing God's presence or help. The best choice depends on the context.