kau- / Indo-European roots
To hew, strike.
a. hew from Old English hēawan, to hew;
b. haggis, haggle; hacksaw from Old Norse höggva, to cut;
c. hoe from Old French houe, a hoe. a-c all from Germanic *hawwan.
2. hag2 from a source akin to Old Norse högg, a gap, a cutting blow, from Germanic *hawwō.
3. hay from Old English hīeg, hay, cut grass, from Germanic *haujam.
4. Suffixed form *kau-do-. incus from Latin cūdere (< *caudere), to strike, beat.
[Pokorny kāu- 535.]