The Collaborative International Dictionary of English v.0.48:
Desideratum \De*sid`e*ra"tum\, n.; pl. Desiderata. [L., fr. desideratus, p. p. See Desiderate.] Anything desired; that of which the lack is felt; a want generally felt and acknowledge. DesidioseWordNet (r) 3.0 (2006):
desideratum n 1: something desired as a necessity; "the desiderata for a vacation are time and money"