互 means “each other, mutual”

たがい · tagai

Also: mutually, reciprocally, together

Kun'yomi (Japanese reading)
たがい, かたみに
On'yomi (Chinese reading)
ゴ

JLPT N3 · Taught in secondary school · 4 strokes

The story

Picture two hooks locked into each other between a top and bottom bar, each holding the other up. お互いさま, said when neighbors help each other out, means it's mutual: next time it'll be your turn.

Used in お互い (otagai, each other), 交互 (kougo, alternately), and 相互 (sougo, mutual)

More from Ties & Differences

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Readings from KANJIDIC2, © EDRDG, CC BY-SA.