The closer words are together, the more likely they are to work together to determine meaning. For example, if the words "electric" and "vehicle" appear 200 words apart in a long paragraph, chances are the subject is not replacements for gas-driven automobiles. But if the words "electric" and "vehicle" are within a very few words of each other, as in "electric powered vehicle" or "electric outlet to recharge her vehicle", the context is much more likely to be on target for a search on vehicles that run on electricity.
In other words, if search findings are presented according to proximity (nearness) of desired words, the more likely you can find the content that you want.
Here is an experiment. Search at this site for any combination of two or more words. For example, type in "that they may be one", then click on "Search". Look at the order in which results are presented to you. The first few may have no waste words at all -- that is, all words you asked for are right together. Then there might be "hits" with one waste word, for example, "that they may all be one". Next will be those with two waste words, for example, "that they may be joined as one". The further down you go, the more waste words there are. Whatever your choice of words, chances are that the results that are near the top of the list are a lot more useful to you than the hits further down the list. Closeness of fit / nearness / proximity gets at meaning. That's because in most languages, meaning is communicated by associating words with other words close by. Language works that way.
Don't you wish all search engines worked that way?
Headings are proximate too. If a word or phrase occurs in a heading, there is strong reason to believe that paragraphs or records under that heading are related. Therefore, words in headings are counted as if they are near all the words within a paragraph or record. Remember that the object is get at meaning. This way of involving headings helps.
Why another search engine? Here is why.
by Marpex, Inc.