For me and for the majority of Ktzat Ivrit’s readership (except those in the southern hemisphere), it’s flu season.
A useful Hebrew word to know is that for bacteria – חַיְדַָקִים (khah-ee-dah-KEEM). This is the plural. A single bacterium is a חַיְדַּק (khah-ee-DAHK).
Like the subject of last entry involving the word for the 20th-century advent of the car brakes, bacteria was discovered long after Biblical and Mishnaic times. חיידק is thus a freshly coined (as in, the last several decades) term, cleverly combining the words חָי (KHAH-ee) – living – and דַּק (dahk) – thin or slight (or slender, as a friend of mine from the Land of the Queen Jeremy suggested).
חיידק is also one of the words for germ.