gateway

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. An opening or a structure framing an opening, such as an arch, that may be closed by a gate.
2. n. Something that serves as an entrance or a means of access: a gateway to success; the gateway to the West.
3. n. Software or hardware that enables communication between computer networks that use different communications protocols. Also called router².

Century Dictionary and Cyclopedia

1. n. A passage; an entrance; an opening which is or may be closed with a gate, as in a fence or wall.
2. n. A frame or an arch in which a gate is hung: sometimes extended to the gate-house or gate-tower surmounting or flanking an entrance or a gate, and designed for ornament or defense.
3. n. A means of ingress or egress generally—more frequently of ingress; an avenue; a passage; an approach.
4. n. In coal-mining, same as gate.

Wiktionary

1. n. An entrance capable of being blocked by use of a gate.
2. n. Any point that represents the beginning of a transition from one place or phase to another.
3. n. A point at which freight moving from one territory to another is interchanged between transportation lines.
4. n. digital communications In wireless internet, an access point with additional software capabilities such as providing NAT and DHCP, which may also provide VPN support, roaming, firewalls, various levels of security, etc.

GNU Webster's 1913

1. n. A passage through a fence or wall; a gate; also, a frame, arch, etc., in which a gate in hung, or a structure at an entrance or gate designed for ornament or defense.

WordNet 3.0

1. n. an entrance that can be closed by a gate