desideratum

noun

Etymology: Learned borrowing from Latin dēsīderātum (“something that is desired”), neuter nominative singular of dēsīderātus, the passive past participle of dēsīderāre (“to desire”), from dēsīderō (“to desire, want, wish for”), from de- (intensifying prefix) + possibly sīdus (“star; constellation”) though the connection is unclear. The English word is cognate with French desideratum, Spanish desiderátum. The plural is derived from Latin dēsīderāta.

1. Something that is wished for, or considered desirable, particularly when thought to be essential.

   “It having hitherto been a deſideratum to draw ſilver wire fine enough for aſtronomical uſes, our author's improvement "conſiſts in nothing but in flattening the fineſt wires which are now drawn."”

   “I shall now, agreeably to your request, endeavour to point out some of the principal Desiderata of the science of Natural History, and the most effectual means to be pursued for the Advancement of Science.”