"Roche" as in the geographical/glaciological term "Roche moutonnée "
Literally "muttoned rock" which I was told, wrongly, at school they were called cos they looked like a sheep viewed from its back end.
In fact the term was made thus for a different reason.
"The 18th-century Alpine explorer
Horace-Bénédict de Saussure coined the term
Roches moutonnées in 1786. He saw in these rocks a resemblance to the
wigs that were fashionable amongst French gentry in his era and which were smoothed over with
mutton fat (hence
moutonnée) so as to keep the hair in place.
[1] The French term is often incorrectly interpreted as meaning "sheep rock" ".
But TBH they are Ferrero roch
ers qhich means a rock or a boulder, as opposed to "roche" which means "rock" as in the material. i.e. stone, but can also mean
a rock.
They are fairly interchangeable unless you are talking about stone, the material.
I am a little surprised you didn't work it out from the context, plus the fact the first 3 letters are the same. But these things happen and it isn't always obvious.
I once really screwed up an English comprehension exam at school, which I originally thought was about a Naval action until I read the term "Battlewagon" which I had never come across before. From that point in I assumed they were talking about a tank and it was a land battle. You'd be amazed hpw the text seemed to read fine in both contexts.