taḫsistu *
1) 
: a reminder , a memory-trigger , especially : a memorandum written ;
2) literary : 
: ṭuppi taḫsistu : remembrance , recollection , memory ;
Cf. hissutu, ḫasāsu (Š), ḫasīsu, atra ḫasīsi, ḫassu, lā ḫāsisu, ḫasāsu, ḫāsisu, Atram ḫasīs, Atar ḫasīs