This the number of times each day that people search for this term in Google. We base this on an "exact match" count. We use a local search volume metric from Google, so the numbers reflect searches done in the US (on google.com) or on google.co.uk if you are looking at UK data....

Since it is daily search volume, the number will be smaller than what you would see as its "monthly searches" stat on the Keyword Overview page.