blood-alcohol

The compound term "blood-alcohol" is a modern scientific and legal construct, formed by directly combining two established English words. "Blood" has ancient Germanic roots, referring to the vital fluid, while "alcohol" has a more complex journey from Arabic 'al-kuḥl' (referring to a fine powder used as eyeliner) through Latin to denote the essence or spirit of a substance, and eventually the intoxicating component of fermented liquids. The logic of the compound is transparently descriptive: it specifies the particular bodily fluid and the specific chemical compound being measured within it, creating a precise term for forensic and medical quantification.

Structure: blood (fluid) + alcohol (intoxicant) - blood: From Old English 'blōd', of Germanic origin. Functions as a noun indicating the red fluid circulating in the body. - alcohol: From Medieval Latin 'alcohol', originally meaning a fine powder, later applied to distilled spirits. Functions as a noun indicating the intoxicating agent in drinks.