The American Heritage® Dictionary of the English Language, 4th Edition
n. Something considered necessary or highly desirable: "The point is not that the artist has 'penetrated the character' of his sitter, that commonplace desideratum of portraiture” ( Robert Hughes).
n. Something that is wished for, or considered desirable.
the GNU version of the Collaborative International Dictionary of English
n. Anything desired; that of which the lack is felt; a want generally felt and acknowledge.
The Century Dictionary and Cyclopedia
n. Something desired or desirable; that which is lacking or required.
WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
n. something desired as a necessity
Word Usage
"The only social desideratum from the perspective of justice might be some H, but a principle of fairness might constrain the way H is allocated, such that it’s not required to feed everyone to the Utility Monster, if there are any in the society."