“pain,” “grief,” “suffering” — combining form denoting pain
The word entered English in the 1870s as analgesia (noun), borrowed from Modern Latin analgesia, from Greek ἄλγος (algos) — literally “pain.” The root algos (“pain”) connects alg- to the entire pain and sensation roots: analgesia (an- + alg- + -ia → absence of pain), neuralgia (neur- + alg- + -ia → nerve pain), and myalgia (myo- + alg- + -ia → muscle pain). The combining formalg- is highly productive in neurology, rheumatology, and pain medicine: e.g., analgesic, arthralgia, fibromyalgia, and hyperalgesia.