the mind > possession > retaining > sparingness or frugality > [noun] > thrift or economical management > means of (3)
A sparing, frugal, or thrifty person; one who spares in using anything.
A means for preventing loss or waste, sometimes (depreciative) as contrasted with something which makes positive gains or profit. Now rare.
Something which saves labour, time, money, or resources; a means of economizing. Frequently with of or as second element in compounds.