meter measure
"Meter" is a Greek root. It comes from the Greek word "metron," which means measure.
Assuming you mean cred- as in incredible, credibility, etc., it comes from the Latin word credere (to believe).
uni (latin) mono (greek) both of them mean one
Yes. tetranocular mean four eyes in Greek and Latin
Yes. Equinomorph does mean horse-shaped in Greek and Latin.
Yes. Heptanocular mean seven eyes in Greek and Latin
Yes. Psychovore does mean mind-consumer in Greek and Latin.
Yes. Hematovore does mean blood-consumer in Greek and Latin.
No, it's from Greek meter "mother" and polis"city."
Demeter is not a Roman name, so has little meaning in Latin, it is Greek and the meaning is "Earth (De=Ge) Mother (Meter)".
It is correct to say biantibrachial mean two forearms in Greek and Latin.