KanjiJLPT N1
String

string, cord, braid, lace, tape, strap, ribbon

Mnemonic

Grandma knits a string so long it wraps around the whole house. A penguin waddles in, trips over the string, and gets tangled up. Grandma calmly unwinds the penguin, ties the string into a neat bow around a gift box, and hands it to the grateful bird.
Additional thoughts
Picture grandma in her rocking chair, yarn trailing everywhere, and a cartoon penguin hopelessly wrapped up like a mummy. The string is the connection between these two unlikely characters.
Quick recall
Grandma's string tangles up a clumsy penguin.

Details

The keyword for 紐 is string. This kanji refers to a thin cord, string, or strap used for tying or binding things together. It often evokes the image of a narrow band of fabric or thread, such as those used to fasten clothing, wrap packages, or secure objects. In a broader sense, it can also represent ties or connections between people or things.
On'yomi
ちゅう、じゅう
Kun'yomi
ひも

Used in vocab