glacier mill vs sloping trough

glacier mill and sloping trough both are nouns.

Word	Noun	Adjective	Verb	Adverb
glacier mill	Yes	No	No	No
sloping trough	Yes	No	No	No

As nouns, sloping trough is a hypernym of glacier mill; that is, sloping trough is a word with a broader meaning than glacier mill:

glacier mill: a chute through which supraglacial water enters a glacier, boring either to the bedrock or to the depth of common crevasse formation
sloping trough: sloping channel through which things can descend

Other hypernyms of glacier mill include chute, slide, slideway.

glacier mill (noun)	sloping trough (noun)
a chute through which supraglacial water enters a glacier, boring either to the bedrock or to the depth of common crevasse formation	sloping channel through which things can descend