Questions & Answers about Ο εγκέφαλος λειτουργεί συνεχώς.
ο is the definite article, meaning the.
Here it agrees with εγκέφαλος and tells you that the noun is:
- masculine
- singular
- nominative (the subject form)
Greek uses the definite article more often than English does. In general statements like this one, Greek often says ο εγκέφαλος where English might say either the brain or just talk about brain more generally.
ο εγκέφαλος is:
- masculine
- singular
- nominative
It is the subject of the sentence, so nominative is the expected case.
Also, -ος is a very common ending for masculine nouns in Greek, though it is not exclusively masculine in all cases. In this sentence, the article ο makes it clear that εγκέφαλος is masculine.