Labialization

Labial(-velar)ized with protrusion (rounded lips)
◌ʷ
Encoding
Entity (decimal)ʷ
Unicode (hex)U+02B7
Labialized with compression (flat lips)
◌ᵝ
Encoding
Entity (decimal)ᵝ
Unicode (hex)U+1D5D

Labialization is a secondary articulatory feature of sounds in some languages. Consonants pronounced this way are said to be labialized and are usually transcribed in the International Phonetic Alphabet by affixing a superscript w, ⟨ʷ⟩, to the base letter. Labialized sounds involve the lips while the remainder of the oral cavity produces another sound. The term is normally restricted to consonants. When vowels involve the lips, they are called rounded.

In phonology, "labialization" may also refer to a type of assimilation process.