What does the underscore (_) wildcard signify in textbox filtering?

The underscore (_) wildcard is used in textbox filtering to represent a single, missing character within a string. When applied, it allows users to search for terms that can vary by a single character position, making it useful for filtering results that might have slight variations. For example, if you were to input "a_c" in a textbox filter, it would return results such as "abc", "axc", or "a1c", where any character can occupy the underscore's position.

This functionality enhances the flexibility and precision of search queries, enabling more nuanced data retrieval that accounts for irregularities in naming or formatting. The underscore's role is specifically about filling in gaps for individual characters, rather than matching entire phrases or sets of criteria.