Is there a word in Old Norse vocabulary for Balts (Baltic people)? How about regions of nowadays Latvia, particularly for Courland?
Not exactly what you're asking, but an Old English text reporting the journey of two Scandinavians through Finnish and Baltic territory uses the phrase "Estland" for the region on the east coast of the Baltic Sea (http://www.oereader.ca/Wulfstanfram.html). Since the text was supposedly transcribed from Norse visitors, we might assume that "Estland" was an Old Norse term borrowed by Old English scribes. This word is cognate to many modern Germanic words for Estonia, which might suggest that it does refer to the Finno-Ugric-speaking people living in the Baltic region that would later become Estonia, but not the Baltic people you are asking about.
Then again, the Old English text describes this territory as a vast region with many cities and rulers ("Þæt Estland is swyðe mycel, and þær bið swyðe manig burh, and on ælcere byrig bið cynincg"). Given this, it seems like the term might be vague enough to refer to the whole region and not just to the part inhabited by Estonians. This is made more plausible by the fuzziness of ethnolinguistic boundaries in early medieval times, especially to a foreign visitor to the Baltic region like the Norse narrator of the text.