"The word "Pontiakós" can have two related meanings:

It refers to the Greek dialect spoken by the Pontic Greeks, an ethnic Greek population that has historically inhabited the Pontus region in northeastern Asia Minor (modern-day Turkey) for millennia. Due to the political situation in the region, many Pontic Greeks were forced to migrate to other parts of Greece and the world during the 20th century, resulting in a diaspora.
Of or relating to Pontus: More generally, "Pontiakós" can refer to anything related to Pontus, the historical region in northeastern Asia Minor. This could include the history, culture, or geography of the region.