By default, the search will return not only the matches with the required word but also matches containing words stemming from the required words.

In plain english this means that if you enter 'AIRLINE' as a search word, the engine search will return matches with words stemming from 'AIRLINE' like:
AIRLINE
AIRLINES
AIRLINER
US AIRLINES etc...

Analogue to that, if you enter 'GOLF', you will also get matches like:
GOLF
GOLFER
GOLF COURSES
GOLF CART etc...

HOWEVER, this is not always desirable.
For example, if you enter 'CROW' - you will get matches with words like:
CROW
CROWN
CROWD
CROWBAR etc...

This is why in our advanced search you can choose whether to use stemming or not.