strew-
“to spread, strew, scatter”Source of Latin struere, English strew, structure, destroy
Root for spreading or layering, yielding Latin struere (to build) and English structure, destroy, strew.
Discussion
The PIE root *strew- (to spread, to strew, to scatter across a surface) produced the vocabulary of spreading and the surfaces produced by spreading — a word family connecting the act of scattering rushes on a floor to the geology of rock strata and the engineering of paved streets.
English strew (OE strēowian, "to scatter, to spread") continues the root natively. The past participle strewn preserves the archaic strong-verb form. German streuen (to scatter, to strew) confirms the Germanic cognate.
Latin sternere (to spread, to lay flat, to pave) continues the root in Italic through the nasal-infix present characteristic of Latin: strāt- (past participle stem) gave English: stratum (a spread-out layer), strata (plural — geological layers), stratify (to arrange in layers), street (via Latin strāta via, "paved road" — the road is that which has been spread/laid flat), and prostrate (prō-strātus, "spread flat before" — thrown face-down). The military term stratagem connects through Greek stratēgós (general — one who spreads out armies).
The root's connection to *ster-neh₂- (the extended form meaning "to spread flat" — see the separate entry) shows the PIE derivational system at work: *strew- is the base, *ster-neh₂- adds the transitive/causative suffix.
The conceptual chain spread → layer → road → layer of rock → social stratum encodes a remarkably consistent image: everything that is stratified has been spread out in layers, whether by human hands (streets, floors) or geological processes (strata).