late 14c., of units in a grouping, "disunified and dispersed," past-participle adjective from scatter (v.). Figurative use, in reference to thoughts, etc., is by 1620s. Related: Scatteredly.
Entries linking to scattered
scatter v.
mid-12c., scateren, transitive, "to squander;" c. 1300, "to separate and drive off in disorder;" late 14c., "to throw loosely about, strew here and there," possibly a northern English variant of Middle English schateren (see shatter), reflecting Norse influence. The intransitive sense, "go or flee in different directions, disperse" is from c. 1300. As a noun from 1640s, "act or action of scattering;" by 1950 in reference to radio waves.
scatterbrain n.
also scatter-brain, "thoughtless, giddy person; one incapable of serious, connected thought," 1790, from adjective scatter-brained "careless, giddy" (1764); see scatter (v.) + brain (n.). Scattered in the figurative mental sense is by 1620s, and the use of scattering for "mental distraction" dates to mid-15c. For the formation, compare scatter-good "spendthrift" (early 13c. as a surname).