Kwukyel mark

It marks the Korean syllable 호 in kwukyel annotation. Kwukyel (also called gugyeol) is a Korean reading system: readers inserted shortened Chinese characters or marks into Classical Chinese, an older written form of Chinese, to supply Korean grammar while reading. For 乊, the recorded written source is the upper part of 乎.

The broader practice goes back to the Silla period, an early Korean kingdom; that dates the annotation system, not this specific mark. The wider Silla writing tradition is described as influencing Japanese katakana and okoto-ten, a Japanese system of reading marks. That is a connection between writing traditions, not evidence that 乊 itself became a Japanese character.

Why do references connect 乊 with 伊?

They reflect different cataloguing traditions. Korean references label 乊 as 구결자 호, a kwukyel mark for the syllable 호; one Chinese dictionary lists it as equivalent to 伊, a separate Chinese character. These entries are reference labels, not several everyday meanings to swap between.

What should I make of 乊 alone?

Ask what text or source it came from. Its documented role is a historical reading mark, so the surrounding text or the sender’s source is the useful clue.