What are common structural words called? [duplicate]

I'm thinking of words that appear in sentences which exist primarily to give structure. So examples might be:

"a" "of" "and" "are"

For example, when searching on Google for a phrase like "catch a butterfly", the results list will show bold highlights of the exact phrase, or isolated occurrences of "Catch" or "Butterfly" but it will not bold isolated occurrences of those structural words listed above.

Is there a name for this type of word? Also, is there a list of these words somewhere? I ask because I'm implementing a similar highlighting feature and want to exclude all the single occurrences of words which aren't germane to the searched term.

Solution 1:

In Web Search (or general text Search) , these words have a technical name "STOP WORDS", and a list of such words has a technical name "STOP LIST", which consists of your examples and many many more words.

Basically, STOP WORDS are those which are very common, do not add meaning to the query and not really good enough to filter the DataBase or Corpus.

Explore more here:

https://pythonspot.com/nltk-stop-words/

https://codingcanvas.com/full-text-search-stoplist-and-stopword/

https://nlp.stanford.edu/IR-book/html/htmledition/dropping-common-terms-stop-words-1.html