to cover or shield (something or somebody) from injury or destruction
to guard or defend (something or somebody) against attack, harm, danger, etc
to take measures to save (an endangered species) from extinction
to shield or foster (a home industry) by an import tariff
to provide funds to guarantee payment of (e.g. a bill of exchange)
[Latin protectus, past part. of protegere, from pro-1 + tegere to cover]