子子孫孫
shi.shi.son.son

Literally: child – child – grandchild – grandchild

Alternately: One’s children and grandchildren; one’s descendants; posterity; until the end of history.

Notes: Each repeated character may be written with the repetition mark 々; the second 孫 (in either form) may be voiced as zon.

This phrase is an emphatic doubling of 子孫 (shison), “descendant.” It comes to us from the Book of Documents (Shujing), a truly ancient collection of rhetoric that we’ve met before.

I guess Zoro’s a bit of a punster