Words with IE in the middle:dieddiesdietliedliespierpiespriesttiedtierties
sauce
OMELETTE
Words with "te" in the middle:litersmeters
Some six letter words with FF in the middle are:wafflebafflebufferduffermufflepifflesufferduffelpuffindiffer
Cobra
Some words that have the letters ME twice in the middle are:amendmentcommencementdismembermentmeantimemeasurementmementomerrimentmesmerisemetronomesometimesummertime
Year 1000 was approximately in the middle of the Middle Ages
bookboombootcookcoolcoopcootdoorgoodgoongoophoodhookhooplookloonloomlooplootmoodmoonmoornookpoofpoorpoolrootrookroofroomsoonsoottoottooktoolwoodwoolwoofzoom
Some six letter words with OOS in the middle:IgloosKazoosWazoosYahoos
A real word is trekker, a slang word is likker.
ace, act, ice, icy, oca