This is the 1308th most frequent Japanese word.
置い
The term "置い" is the stem form of the verb "置く" (oku), meaning "to place" or "to put."
The word '置い' here is part of the verb '置いた', meaning 'placed'. It describes the action of putting something in a specific location. It is in the past tense.
テーブルに本を置いた。
I placed the book on the table.
In this sentence, '置い' is used in the continuative form '置いて', linking the action of placing the box with subsequent actions.
彼は箱を床に置いて離れた。
He placed the box on the floor and walked away.
Here, '置い' is part of '置いて', used metaphorically to describe keeping or storing something intangible, like a thought, in a location such as the mind.