This is the 343rd most frequent Spanish word.
martín
"Martín" is a male given name in Spanish, equivalent to "Martin" in English.
In this sentence, 'Martín' is used as a proper noun to name a person.
Martín es un buen amigo mío.
Martín is a good friend of mine.
Here, 'martín pescador' refers to a species of bird, the kingfisher.
El martín pescador es un ave muy veloz.
The kingfisher is a very swift bird.
'Martín' is again used as a proper noun, but this sentence also implies a change of location.