etaoin shrdlu

Etymology
From the arrangement of letters on the keyboard of a linotype machine: typesetters would mark errors by running their fingers across the keys, and the results would sometimes accidentally find their way into print. The letters in the string are, approximately, the 12 most commonly used letters in the English language, ordered by their frequency, which drove the design of the linotype keyboard.

Noun

 * 1) Nonsense, filler text (dummy text), or an example of accidental typing (typo).