The NOT operator excludes words from any results. So the search query abba AND agnetha AND frida NOT bjorn NOT benny would result in Web pages that include the word abba and mention the women's names, but exclude pages that also references to Bjorn and Benny, the male members of Abba. There are shortcuts to these operators, which can be very useful. All words would be found in the pages listed in the search results. They define phrases.
Brackets are useful too.
You can mix and match all these techniques to do fairly elaborate searches. The results would not contain the word london . Hopefully you would get results that talked about the musical called Mamma Mia featuring Abba music but excluded pages that referred to performances in London. Now go put on the Abba tune Dancing Queen and celebrate. Make sure you pull down the blinds so you don't embarrass yourself in front of the neighbours.