Definitions of dilution
(COMPANY LAW) a reduction in the earnings per share of ordinary shares, often the result of a company issuing additional shares
The rights issue resulted in a dilution of the share value.
(INTELLECTUAL PROPERTY LAW) a subset of trade mark law which forbids the use of a famous trade mark in a manner that reduces the mark's uniqueness or distinctive character
The use of the famous NIKE trade mark on poorly-made bicycles was the subject of a dilution claim.