Ingress, n.
Etymology: [L. ingressus, fr. ingredi. See Ingredient.]
1. The act of entering; entrance; as, the ingress of air into the lungs.
2. Power or liberty of entrance or access; means of entering; as, all ingress was prohibited.
3. (Astron.)
The entrance of the moon into the shadow of the earth in eclipses, the sun's entrance into a sign, etc.
1 other Webster entry under this spelling
Ingress, v. i.
To go in; to enter. [R.]
Shades of meaning
Fernald has no entry of its own for ingress; he lists it under entrance.
He lists it without comment; the entries above explain its neighbors.