eye'glos ('eye' represents the pronunciation of that English word, with the same pronunciation holding for either alternative spelling)
There are two variant spellings of this spear's name,
Aiglos and
Aeglos (though in fact these are pronounced in the same way, and would be written identically in
Elvish characters).
Aiglos is the spelling in most earlier editions of
The Lord of the Rings, but has been adjusted in more recent editions to
Aeglos, as a more strict transliteration of the
Sindarin name.