井|いi[1]atamadaka (head-high)

1. nounwell
   井いの中なかの蛙かわず、大海たいかいを知しらず。↗

   He who stays in the valley shall never get over the hill.

• Synonym井戸いどNeutralThe everyday word for a water well and the most common choice, as in 「井戸を掘る」.
• Related井泉せいせんWrittenWritten/formal prose word for a well or well water; rarely used. 「井（い）」 itself appears mostly in set phrases like 「井の中の蛙」.

For an everyday water well use 「井戸」; 「井泉」 is a written/formal-prose alternative. Keep 「井」 for old or idiomatic uses such as 「井の中の蛙」.

Usage comparisons are AI-assisted and cross-checked by multiple models; for study reference only

1. （い）井戸いど。