What ई means
It is the independent long i vowel.
In Hindi, it begins a written syllable without a preceding consonant. The ancient Indian language Sanskrit pairs it with short इ; after consonants, ी carries the same long vowel, as in की.
Devanagari grew through earlier scripts
Brahmi, an early Indian script, appears on Ashoka’s stone inscriptions in the third century BCE. Gupta and Nagari forms led to Devanagari in the 7th century CE; the script matured around the 13th century. Its short/long vowel pair records vowel length. Print and language politics linked the script with Standard Hindi in the 19th–20th centuries.
Don't confuse it with
1Questions people ask
1Why does ई show as a box on some devices?
Because that device's fonts have no glyph for it. The character is still correct and still copies correctly — the box is a missing glyph, not a broken character.
How to type ई
ई\0908Codes and encoding1 code points
A visible symbol can contain several code points. JS .length counts UTF-16 units; UTF-8 counts bytes.