One's Seal, Seal, Personal Seal
noun
The child of a judge is the thing he puts on his judgements. What does he put on his judgments? His seal, you know, to make it all official and stuff.
はんこ
判 is the reading you learned. 子 is the kun'yomi vocab reading, which I bet you know pretty well by now as well. You just have to remember to use it here.
判子屋さんで、判子を注文しました。
I ordered my personal seal at a seal store.
ここにはサイン、そこには判子をお願いします。
Please sign here and put your seal there.
この書類には、コウイチによって公的な判子が押されています。
This document was officially sealed by Koichi.