U+0153 Latin Small Ligature Oe

The Wikipedia has the following information about this codepoint:

Œ (minuscule: œ) is a Latin alphabet grapheme, a ligature of o and e. In medieval and early modern Latin, it was used in borrowings from Greek that originally contained the diphthong οι, and in a few non-Greek words. These usages continue in English and French. In French, the words that were borrowed from Latin and contained the Latin diphthong written as œ now generally have é or è; but œ is still used in some non-learned French words, representing open-mid front rounded vowels, such as œil ("eye") and sœur ("sister").

It is used in the modern orthography for Old West Norse and is used in the International Phonetic Alphabet to represent the open-mid front rounded vowel. In English runology, œ ɶ is used to transliterate the Runic letter odal (Old English ēðel "estate, ancestral home"). Its traditional name in English is ethel or œthel (also spelt, ēðel, odal).