Eversion - significado de eversion diccionario
f. eversion, outward turning, esp. of the mucosa surrounding a natural orifice.
Boy's surface is an immersion of the real projective plane in 3-space; thus also a 2-to-1 immersion of the sphere. The Morin surface is an immersion of the sphere; both it and Boy's surface arise as midway models in sphere eversion.