We say ‘My danders up now’. What is Dander?
Google led me here and the suggestion that:
‘Dander is an informal term for a material shed from the body of various animals, similar to dandruff. It is composed of skin cells. It is a cause of allergies in humans.
Older etymology has it that dander is a rare (perhaps Yorkshire) synonym of dandruff (OED). In the idiom “getting one’s dander up” the colloquial meaning, anger, is probably unrelated to the above usage.
Which came as a relief really.
The real OED includes the dandruff definition but adds one or two more usages including slag from a furnace or a stroll or a saunter or the most likely candidate – to be in a ferment – like the ferment used in making molasses in the West Indies. As the Free Dictionary adds ‘By extension ferment means ‘agitation or tumult.’
Which makes sense. First recorded use was in 1831 apparently.