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# What are "Boolean operators"?

Searching on the internet is pretty straightforward, but there are a few tips and tricks that might help you. One of them is to understand ‘Boolean operators’ (where they’re still in use). This short guide will tell you what they are.

Guy Clapperton | 9th September 2010

Boolean operators are part of what makes some search websites work. Most people get by on the internet without ever having any knowledge of their existence, but they do have their uses.

## What are they?

Essentially, Boolean operators are what governs the definition of the plus sign (“+”), the minus sign (“-“) and the words “and” and “or” when you doing a search on the internet. You probably think you understand “and” and “or” quite happily, thanks, and for most purposes you’d be right.

But in some cases, a lot of people use them in a way a computer would misunderstand. For example, if you asked the author of this article what he’s wearing on his feet at the moment, he’d say “shoes and socks”. If you asked him what he wears on his feet in general, he might say “shoes, socks, wellies, slippers and sandals”.

And yet when you think about it, this isn’t the right answer, because the word “and” suggests – in the strictest interpretation – that he wears all of those things at the same time. And, I can assure you, I don’t!

The correct answer, as understood by a computer, would be “possibly socks and either wellies, slippers or sandals”. The human reader understands that anyway - the computer, frustratingly, won’t have a clue.

## Boolean logic

So if you were searching on the internet, there are a few things you need to know about Boolean logic.

Firstly, if you search for “boots and socks”, many search engines will perform four searches - one for each individual word and one for any combination of them. If you put the three words in quote marks, then it will search for the whole phrase.

If you mean “or”, then put “or”. Otherwise it will assume you want a site that has something to do with all of them.

It’s the same with the plus sign and the minus sign – all of these things have to mean exactly what they say if you’re going to come out with a meaningful answer at the end.

Please note - the search engines constantly change the way in which they operate so that people can’t trick the system into putting their pages to the top of every search. So, although asking a meaningful question and using search terms carefully is always good, the Boolean rules underlying it might be out of date at any time.

## Guy Clapperton

Guy Clapperton is a journalist specialising in writing about technology as well as small business for several major broadsheets. He broadcasts occasionally on BBC Radio stations and reviews the newspapers on the BBC News Channel.