Colloquial, somewhat childish or friendly word for 'side' or 'sideways'. Often used in casual speech, especially when talking about the side of something or moving sideways.
Please move over to the side.
The name is written on the side of that box.
Derived from 横 (よこ, 'side') with the colloquial suffix っちょ, which adds a casual, diminutive, or childlike nuance. The exact origin of っちょ is uncertain, but it appears in several informal words.