1. Words and expressions with an abnormal number of letters or syllables: "While ped may refer to a foot as a measure of length, it can also refer to what the Roman poet, Horace, spoke humorously of as, sesquipedalia verba; words which are a 'foot and a half long' and which exist in English as sesquipedalians with the same meanings."
2. A person or thing that is a foot and a half in height or length: "The hikers were startled to see the footprints in the snow that were obviously sesquipedalians in size and which made the hikers wonder if a mountain monster lived in the area."