Noun blue devil has 2 senses
- blueweed, blue devil, blue thistle, viper's bugloss, Echium vulgare - a coarse prickly European weed with spikes of blue flowers; naturalized in United States
--1 is a kind of depression; herb, herbaceous plant; depression; herb, herbaceous plant
--1 is a member of Echium, genus Echium
- amobarbital sodium, blue, blue angel, blue devil, Amytal - the sodium salt of amobarbital that is used as a barbiturate; used as a sedative and a hypnotic
--2 is a kind of amobarbital; amobarbital
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