Header rhymes with:
cheddar, deader, eder, fedder, feder, fedor, leder, lehder, maeder, medar, prijedor, raeder, redder, reder, rehder, schraeder, shredder, spreader, tedder, vedder
Header sounds like:
hader, hadria, haider, hater, hatter, hattery, hattori, haueter, hauter, hayter, headwater, heater, heather, heathrow, heeter, heider, heidiwear, hider, hither, hitter, hodder, hoddur, hooter, hotter, hotwire, huether, hutter, hyder, hydra, hydro