gripo

Named for how it arrives. French gripper is to seize, to grab hold, and the illness got the name because that is what it does: influenza does not creep up on you over three days the way a cold does, it puts you on the floor in an afternoon. English borrowed the French word as grippe and kept it as a slightly old-fashioned alternative to flu, while influenza itself came from Italian by a different road entirely, from the astrological influenza - the influence of the stars, which was the best available theory at the time.

The fence with a cold matters clinically. A gripo is influenza. A common cold is malvarmumo, built out of malvarma with the -um- suffix, roughly the thing you get from the cold. Esperanto keeps them apart as firmly as any doctor would, and a learner who calls every winter sniffle a gripo is overstating the case in Esperanto exactly as in English. Gripa is the adjective and gripi is to have the flu.

The vocabulary around it is already yours. Febro at 1,576 is the fever, tusi at 2,622 is to cough, kapdoloro at 1,887 is the headache, and a simptomo at 2,474 is any one of them. A viruso at 2,057 is the cause, an epidemio is the whole town having it at once, and vakcino is what stops it. This chapter and the last two have quietly assembled most of a medical vocabulary.