Conference is a type of Discussion. Conference is a type of Meeting. Forum is a type of Meeting. 
Curriculum is related to Course. Course is related to Trail. Trail is related to Ridge. Ridge is a type of Cover. 
Discussion <--IsA-- Conference --IsA--> Meeting <--IsA-- Forum 
Curriculum <--RelatedTo--> Course <--RelatedTo--> Trail <--RelatedTo--> Ridge --IsA--> Cover 