Domain is related to Class. Class is related to Instance. 
Meaningful is a synonym of Deep. Deep is related to Concern. Concern is related to Worried. Worried is related to Fear. 
Domain <--RelatedTo--> Class <--RelatedTo--> Instance 
Meaningful <--Synonym--> Deep <--RelatedTo--> Concern <--RelatedTo--> Worried <--RelatedTo--> Fear 