Describing an experiment (usually medical) in which some information which might influence the experiment is withheld from two parties. Most commonly, parties in question are the subjects and the administrators and the information which is withheld is the treatment groups of the subjects.

plural of double-blind test

(sciences) A form of scientific testing in which some information is withheld from two different parties. Most commonly, neither the tester nor the subjects tested know which are the control items and which are the test items.