I've always understood it using the 'source' and 'destination' analogy that many unix tools follow. Credit is the source while debit is the destination. Using

I've always understood it using the 'source' and 'destination' analogy that many unix tools follow. Credit is the source while debit is the destination. Using the source and destination keywords has the advantage of not implying the actual operation to be performed. For eg. credit results in an 'add' operation on an expense account while a 'subtract' operation on an asset account.