Definition: used to refer to a person, object, idea, etc. that is separated from the speaker by space or time; used to refer to something that has been mentioned or was involved earlier, or to something that is already known about.
Note: that sign is inflected to the subject-determiner agreement.
Formal citation; the passive palm in this ASL sign is not frequently used, usually signing THAT without the passive hand. Signing THAT with the passive palm may be used in some circumstances. E.g. "IX-he TOLD ME THAT [emphasis]..." Or, "THAT's WHY".
Review 101 words. Refresher.