bur·den 
(bûrdn)
(bûrdn)n.
1. Something that is carried.
2.
a. Something that is emotionally difficult to bear.
b. A source of great worry or stress; weight: The burden of economic sacrifice rests on the workers of the plant.
3. A responsibility or duty: The burden of organizing the campaign fell to me.
4. A principal or recurring idea; a theme: "The burden of what he said was to defend enthusiastically the conservative aristocracy" (J.A. Froude).
5. Music
a. A drone, as of a bagpipe or pedal point.
b. Archaic The chorus or refrain of a composition.
c. Archaic The bass accompaniment to a song.
6. Nautical
a. The amount of cargo that a vessel can carry.
b. The weight of the cargo carried by a vessel at one time.
7. The amount of a disease-causing entity present in an organism.
tr.v. bur·dened, bur·den·ing, bur·dens
1. To cause difficulty or distress to; distress or oppress.
2. To load or overload.
[Middle English, from Old English byrthen; see bher-1 in the Appendix of Indo-European roots. Noun, senses 4 and 5, influenced by BOURDON.]
Synonyms: burden, affliction, albatross, cross, millstone, trial, tribulation
These nouns denote something onerous or troublesome: the burden of a guilty conscience; considered the television an affliction that destroyed the spirit of community; a poorly built home that became his albatross; an unhappy marriage that became a cross to bear; a routine duty that turned into a millstone; a troublemaker who is a trial to the teacher; suffered many tribulations in rising from poverty. See Also Synonyms at substance.
These nouns denote something onerous or troublesome: the burden of a guilty conscience; considered the television an affliction that destroyed the spirit of community; a poorly built home that became his albatross; an unhappy marriage that became a cross to bear; a routine duty that turned into a millstone; a troublemaker who is a trial to the teacher; suffered many tribulations in rising from poverty. See Also Synonyms at substance.