The word "house" is extended by any number of letters using the truncation character. Thus, in addition to hits containing the word "house", the plural form "houses" will also be found with the aid of truncation.
Note: Naturally, this does not work for all plural forms. In the case of "knife", the plural form is not found with the aid of truncation.
Tip: Depending on the search platform, truncation in the middle of the word is also possible. Check the help section to see if there is a truncation character for a letter in the middle of the word. Then you can use it to replace the letter f. For example, in EconBiz (database for business and economics), you will also find hits with the term "knives" when entering "kni?e*".