small water spring
Archaic noun for a small natural spring or welling water source. Not used in modern everyday Japanese; encountered mainly in classical literature or historical descriptions.
The word 'isara-i' appears in old waka poetry.
Archaic kanji spelling for a small spring; the reading いさらい is not obvious from the characters.
Alternate archaic kanji spelling; both forms are rare and mainly encountered in historical texts.
The derivation is uncertain. The kanji いさら井 and 細小井 are likely ateji or conventional spellings for the native word いさらい, which may be related to いさら (small, fine) and 井 (well, spring).