This is the 7333rd most frequent Japanese word.
井
"井" means "well" (a structure for accessing water).
Here, "井" refers to "井戸," meaning "well," commonly used to represent a water source well.
この村には、古い井戸があります。
In this village, there is an old well.
In this usage, "井" is part of "井桁," illustrating the pattern resembling the kanji character for "well" (井).
井桁とは、井字形に組んだ木枠のことです。
The term "井桁" refers to a wooden frame assembled in the shape of a well character.
Here, "井" connects to "天井," where "井" metaphorically refers to structures or arrangements.