Definition of screes:
(n) :
(uncountable) Loose stony debris on a slope.
(n) :
(countable) A slope made up of scree at the base of a cliff, mountain, etc.
(n) :
(uncountable, by extension) Similar debris made up of broken building material such as bricks, concrete, etc.
(n) :
A harsh, high-pitched sound or cry (as of a hawk).
(v) :
To make a high-pitched cry like that of a hawk.
(v) :
To traverse scree downhill.