Pontus Euxinus.

The two grades gave in Greek two nouns, both enlarged to o-stems, pontos 'sea' and patos 'way, path'.

 

D.Q. Adams in the article "Find"in EIEC states this is derived from *pent- 'find one's way', which gives English 'find'. He gives *pontoh₂s as his transcription for 'untraced path'.

 

Interestingly, the Germanic word that gives English  'path' comes to us via Iranian.

 

In the article "Road", Andrea Della Volpe reconstructs Greek pontos 'sea', to have meant '*path through the sea'.

 

The division in Greek is interesting. This can only be described as a fossil where two allophonic realizations developed separate meanings. Such things do happen, even in modern English.

 

Latin pons 'bridge' (a dry path over water) gets in here too.

 

Pontos is not the usual Greek word for 'sea', 'ocean'. I'm not sure of its exact semantic space. Liddell-Scott-Jones at the Perseus site gives 'sea', 'open sea', and in later Greek, with the sense of a 'special sea'.

 

So. 'Pontus', as in Pontus Euxinus. What's it mean *exactly*. 'Sea' is the glib answer, but there might be something more. 'Watery passage' might be better.

 

This post is not turning out the way I wanted. What struck me was the division in meaning. There is some testimony here on the Greeks becoming sailors.