Where does “infectious mononucleosis” come from?

infectious mononucleosis (English) comes from English mononucleosis, from English nucleus, from Latin nū̆cleus, from Latin nuculea, from Latin -eus, from Ancient Greek -εῖος, from Proto-Indo-European -iHwós, from Proto-Indo-European -wós — Creates adjectives from verb stems.

Ancestry of “infectious mononucleosis”, step by step

infectious mononucleosis traces back through two separate lines of ancestry.

via English mononucleosis

StepLanguageWordMeaning
1EnglishmononucleosisA viral infection marked by extreme fatigue, high...
2EnglishnucleusThe core, central part of something, around which...
3Latinnū̆cleus(small) nut
4Latinnuculeapertaining to a small nut
5Latin-eusargentum + API → argenteus; ferrum + API →...
6Ancient Greek-εῖοςForms adjectives, usually with a meaning of "of"...
7Proto-Indo-European-iHwós
8Proto-Indo-European-wósCreates adjectives from verb stems

via English infectious

StepLanguageWordMeaning
1EnglishinfectiousTransmitted from one person to another, usually...
Every word from Proto-Indo-European -wós