WordWeb Online

1. A gradual sinking to a lower level
   - settling, subsidence

1. Wear off or die down
   "The pain subsided";
   - lessen
    
2. Sink to a lower level or form a depression
   "the valleys subside"
    
3. Sink down or precipitate
   "the mud subsides when the waters become calm";
   - settle
    
4. Descend into or as if into some soft substance or place
   "She subsided into the chair";
   - sink

Type of: come down, descend, dip, fall, go down, go under, settle, sink, sinking, weaken