What's the difference between i.e. and e.g.?
late 14c., from Old French festre "small sore discharging pus," from Latin fistula "pipe, ulcer" (see fistula). The noun is from c.1300. Related: Festered; festering.
fester fes·ter (fěs'tər)v. fes·tered, fes·ter·ing, fes·ters
To form pus; putrefy.