Definition 1
Tag 06IE, permanent. Cite it as [Bourbaki, Tag 06IE].
Algebra, V, p. 20, § 4. Algebraically closed extensions
A field K is said to be algebraically closed if it possesses the (equivalent) properties (AC), (AC'), (AC), (AC).
\* Example 1. — The field C of complex numbers is algebraically closed (Gen. Top., VIII, p. 100). \*
A field K which is relatively algebraically closed in an extension field E of K is not necessarily algebraically closed (in effect every field is relatively algebraically closed in itself, and there exist fields that are not algebraically closed, for example Q or \* or R *). However:
Bourbaki puts the proof directly after the statement, so what is above is the statement and its proof together.