On the cash flow statement and in economics, investment means spending that results in an increase in assets.
This includes capital spending on plant and equipment, i.e. a real increase in the means of production;
but it also includes any swelling of unsold inventory, which can indicate a problem with consumer demand.
Residential investment mainly refers to the purchase of homes.
Annual business and residential investment respectively make up about 12% and 4% of the GDP;
see the interactive GDP Diagram.