Where does “hajko” come from?

hajko (Esperanto) comes from Japanese 俳句, from Middle Chinese 俳 — paralleled.

hajko (Esperanto): haiku

Definitions

Step	Language	Word	Meaning
1	Japanese	俳句	haiku, a poem that usually consists of 5-7-5...
2	Middle Chinese	俳	paralleled

hajko — Etymology, Origin & Word History | Etymology Explorer