atwo

From on + two, already a phrase in Old English as on twā.

atwo (not comparable)

1. In two; in twain; asunder.

   Synonym: atwein

   • 1387–1400, Geoffrey Chaucer, “The Pardoners Tale”, in The Canterbury Tales, [Westminster: William Caxton, published 1478], →OCLC; republished in [William Thynne], editor, The Workes of Geffray Chaucer Newlye Printed, […], [London]: […] [Richard Grafton for] Iohn Reynes […], 1542, →OCLC, lines 388-91:

     Fordronke, as he sat on his bench upright.
     Ther cam a privee theef men clepeth Deeth,
     That in this contree al the peple sleeth,
     And with his spere he smoot his herte atwo

     (please add an English translation of this quotation)