When you search by START of name, END of name or ANYWHERE in name, you can use wildcard characters to help your search.
The wildcard characters are:
_ (underscore), which stands for any single character
% (percent sign), which stands for any sequence of zero or more characters
With these tools you can amaze yourself with sophisticated searches. One of the most helpful searches is for bri_n ANYWHERE in name, which finds "brian" and "brien" (and don't forget to look also for "bryan", "breen", etc). Using both search-boxes, try saint ANYWHERE in name OR st. ANYWHERE in name.
You can be even more devious when using the lower search-box (left of the Island checkbox). For this search-box, negative searches are available, e g NOT ANYWHERE in name. For example (using both search-boxes and selecting the search-logic), try patrick ANYWHERE in name AND st NOT ANYWHERE in name.
The search possibilities are not exactly endless, but they can can certainly be confusing.
To remind yourself of basic techniques, see How to Search
Experiment also with the checkboxes marked Townland, Town and Island. You will find that when you uncheck all three of them at the same time, IreGaz provides results based on which other checkboxes remain checked.