Typed wordsThe longest words typable with only the left hand using conventional hand placement on a QWERTY keyboard are tesseradecades, aftercataracts, and the more common but sometimes hyphenated sweaterdresses.
Using the right hand alone, the longest word that can be typed is johnny-jump-up, or, excluding hyphens, monimolimnion.
The longest English word typable using only the top row of letters has 11 letters: rupturewort.
Similar words with 10 letters include: pepperwort, perpetuity, proprietor, typewriter, requietory, repertoire, tripertite and pourriture. The word teetertotter (used in North American English) is longer at 12 letters, although it is usually spelled with a hyphen.
The longest words typable by alternating left and right hands are antiskepticism and leucocytozoans respectively.