Ethylenediamine tetraacetate. An organic molecule which, due to the chemical groups it contains and their juxtaposition within that molecule, is able to chelate (bind) certain other molecules such as divalent metal cations. EDTA thus inhibits some enzymes requiring such ions for activity.
A transparent compound utilized to prevent blood samples from coagulating prior to conducting tests. Its chemical name is ethylenediaminetetraacetic acid.