[Vocabulary] last

[Maybo]

Mount Etna in Sicily, Italy, is Europe's tallest active volcano. It last erupted in November.

What part of speech is 'last'? Adjective? Does it mean the volcano's last eruption was in Nov 2013?

Source: Mapping Europe

 

[emsr2d2]

What does "last" modify? That should help you work out what it is.

It only means November 2013 if the article was written between January 2014 and October 2014. If it was written recently, it can refer only to November 2016.

 

[Maybo]

What does "last" modify? That should help you work out what it is.

It only means November 2013 if the article was written between January 2014 and October 2014. If it was written recently, it can refer only to November 2016.

I omited the "in 2013".
It should be
"Mount Etna in Sicily, Italy, is Europe's tallest active volcano. It last erupted in November in 2013"
So,"last" is an adverb, motifying"erupted"?

 

[emsr2d2]

I omit​ted [STRIKE]the[/STRIKE] "in 2013".
It should be "Mount Etna in Sicily, Italy, is Europe's tallest active volcano. It last erupted in November [STRIKE]in[/STRIKE] 2013"
So (no comma here) is "last" [STRIKE]is[/STRIKE] an adverb, modifying "erupted"?

See above.

Yes, it's an adverb in that sentence. Have a look at various examples of "last" being used in different ways here.