The kanji 於 primarily conveys the meanings of "in," "at," "on," "to," or "regarding" – indicating a location, a time, or a focus. It functions as a preposition and marks the place, time, or topic of something. It is about indicating the relationship between things in terms of location, time, or subject matter.

・On-yomi (音読み): オ ・Kun-yomi (訓読み): お

⚫︎図書館於勉強する Translation: Studying at the library. ⚫︎会議於決定する Translation: To decide at the meeting. ⚫︎この件において Translation: Regarding this matter.

The kanji 於 is a pictophonetic character. The left side is a component that represents a hand and a stick, or a tree, and the right side is the sound component, which indicates the sound. The original meaning relates to "to be in" or "to be located." The character evolved over time to its current form. It originally showed a person standing or being in a place or on a position.