Where the shape comes from
The mirror-image right half of the same split trunk that gave 爿 its left half — the flat, sliced grain of worked wood rather than the whole round trunk of 木. It stands alone in 片 for any thin flat piece, a slice, a chip, a measure word for photographs and fields, and combines in 版, a printing plate or an edition, and 牌, a placard, a signboard, a plate.
汉字 filed under 片
No published character on HSK Guide is filed under this radical yet. 汉字库.