burden

Noun

• the central idea that is expanded in a document or discourse

• the central meaning or theme of a speech or literary work

• weight to be borne or conveyed

• an onerous or difficult concern
  • the burden of responsibility
    
  • that's a load off my mind
    

Verb

• impose a task upon, assign a responsibility to
  • He charged her with cleaning up all the files over the weekend
    

• weight down with a load

Related words

• Synonyms: 
  effect , essence , core , gist , load , loading , encumbrance , incumbrance , onus , charge , saddle , burthen , weight , weight down
• Antonyms: 
  unburden , disburden