Words from the first week
sesquipedalian < sesqui < semi one half and -que* and + -ped- foot: "a foot and a half in length." Used of words first by Horace verba sesquipedalia -- sesquipedalian words.
SPQR
Senatus Populusque* Romanus
floccinaucinihilipilification < flocci- a tuft of wool or bit of lint + nauci- a trifle + nihili- nothing + pili- a hair + fic < facere make + ation the act of: "the act of making worthless."
"I admired him for nothing so much as his floccinaucinihilipilification of money." (Quoted in the OED -- Oxford English Dictionary). "Floccinaucinihilipilification is the longest word in the Oxford Universal Dictionary." (Quoted in the Idahonian, now the Daily News)
ucalagon "A neighbor whose house is on fire." From Vergil's Aeneid, Book II. At the fall of Troy, iam proximus ardet Ucalagon, "now Ucalagon next door is burning." Ucalagon is also mentioned in the Iliad, as one of the old men on the wall of Troy when Helen passes by.
codex < caudex tree trunk, "an ancient manuscript in book [rather than scroll: volumen > volume < volvere "to roll"] form" -- plural: codices. Derivatives: code, codicil (a supplement to a will < codicillus, diminutive of codex)
hiatus, a gap -- plural hiatus or hiatuses
quiddity < quid what: "the whatness or essence of a thing."
querulous < queri complain: "whining", "complaining".