1585, "structure affording protection," possibly an alteration of M.E. sheltron, sheldtrume
"roof or wall formed by locked shields," from O.E. scyldtruma,
"shield" (see shield
) + truma
"troop," related to O.E. trum
"firm, strong" (see trim
). The notion is of a compact body of men protected by interlocking shields. Fig. sense is recorded from 1588; meaning "temporary lodging for homeless poor" is first recorded 1890 in Salvation Army jargon; sense of "temporary home for animals" is from 1971. The verb is first attested 1590; in the income investment sense, from 1955. Sheltered
"protected from the usual hardships of life" is from 1888.