Most of the time, people just enter a word or phrase for Spotlight to search, but there is some additional syntax that you can use to get better search results.
Here are some types of simple queries you can enter:
- gift card. This will give you any result that has the word 'gift' and the word 'card' in it, not necessarily adjacent. (This is the same as gift AND card.)
- "gift card" (in quotes). This will give you any result that has the exact phrase 'gift card'.
- gift OR card. This will give you any result that contains either word.
- gift NOT card. This returns any result that contains 'gift' but does not contain 'card'
Spotlight offers many more options for making your searches more specific. If you would like to learn more, check out this article from MacWorld.