Ignore All List
When you spell check a file, and Trados Studio finds a word it does not recognize, it displays the Spell Checker dialog.
One of the options in that dialog is Ignore all. When you select this option, Trados Studio adds the term to a list of words that it does not spell check.
Words in the list are shared with all open files in Trados Studio.
In effect, the Ignore all list acts like a dictionary. However, unlike a dictionary, the ignore all list is cleared when Trados Studio starts up.