al·de·hyde 
(ăldə-hīd′)
(ăldə-hīd′)n.
Any of a class of highly reactive organic chemical compounds obtained by oxidation of primary alcohols, characterized by the common group CHO, and used in the manufacture of resins, dyes, and organic acids.
[German Aldehyd, from New Latin al. dehyd., abbr. for alcohol dehydrogenātum, dehydrogenized alcohol.]