Presumably derived from PS *yad- ‘hand’. According to Leslau, Amh. and Hrs. forms, as well as Gez. adverb waˀəda/waˀda/wəˀda contain the deictic element w- (CDG 602).
Amharic
wädä - toward, to, into; around, about, approximately (with numbers)
(AED 1561)