burden
/ˈbɜːdn/
A heavy load.
A responsibility, onus.
A cause of worry; that which is grievous, wearisome, or oppressive.
The capacity of a vessel, or the weight of cargo that she will carry.
a ship of a hundred tons burden
The tops or heads of stream-work which lie over the stream of tin.
The proportion of ore and flux to fuel, in the charge of a blast furnace.
A fixed quantity of certain commodities.
A burden of gad steel is 120 pounds.
A birth.
The total amount of toxins, parasites, cancer cells, plaque or similar present in an organism.