Does this term refer to all kinds of ice, or just 'a slab of ice' in particular?
It seems oighear is used for other types of ice
"The sheet ice" rejected. Hmmm.
I've personally never heard that in English. "Ice sheet", yes. "Sheet of ice", yes. "Sheet ice", no.
For reference, in my region of Scotland (Glasgow) "sheet ice" is often used.
Check out http://www.hoteldeglace-canada.com/ :) But you might not want to stay the night in their bed, if you fear they will take it literally.
We use it in America
Whats wrong with just saying "an t-oighir"?
oighir is the genitive form. Without leac, you would have an t-oighear.
But oighear has a dual meaning, so in normal speech, "the ice" is almost always an leac oighir.
All 3 pronunciations on focloir pronounce the r at the end. Cad é an scéal ansin?
You were listening to the pronunciation of oighear, with a broad r.
The r in leac oighir is a slender r, and she is pronouncing it here.
You can hear the contrast on teanglann.ie (the same recordings as focloir.ie).
You're a fountain of knowledge! Grma