What is "megasthenes"

Megasthenes ( ; , c. 350 – c. 290 BC) was a Greek ethnographer and explorer in the Hellenistic period, author of the work Indika. He was born in Asia Minor and became an ambassador of Seleucus I Nicator of the Seleucid dynasty possibly to Chandragupta Maurya in Pataliputra, India. However the exact date of his embassy is uncertain. Scholars place it before 298 BCE, the date of Chandragupta's death.