1) Latin boy name 
Gratus, a soldier of Caligula`s bodyguard, who, after the assassination of that emperor, discovered and drew Claudius from his hiding-place in the palace, and presented him to the soldiers as a Germanicus, the proper heir to the empire. ...[consul 280] Gratus, possibly named Gaius Vettius Gratus (fl. 3rd century), was a Roman senator who was appointed consul in AD 280. Gratus was probably the son of Vettius Gratus who was consul in AD 250. Gratus himself was appointed consul posterior alongside Lucius Valerius Messalla in AD 280. ==Sources== ...
pleasing, agreeable / grateful.