The Tocharian B word āp
Word āp
a p
IPA ap
Meaning river
See also C. Luwian: ḫa-a-pi-iš ‘river’
Synonyms cake

Comments
Douglas Q. Adams, “Etymological Dictionary of Tocharian B”, 1999, Brill

Other words that might be of interest
war ‘water’, swese ‘rain’, lyam ‘lake’, samudtär ‘sea’, karītstse ‘wet’, asāre ‘dry’, tsrerme ‘ditch’, murye ‘ditch, irrigation’, pält- ‘drip’, kärkkālle ‘marsh, swamp’, waiw- ‘moisten’, kaumiye ‘pond’