You can bond Ethernet ports, often called called "link aggregation" http://en.wikipedia.org/wiki/Link_aggregation
You bond the network adapters in your network configuration, so they appear as one adapter with one IP address.
Of course, the Ethernet cards/ports in both devices would need to support this.
That being said,
Remember, A network is only as fast as it's slowest link.
Most Ethernet connections today are 100 Mbps fast Ethernet using CAT5 or CAT5e UTP cable. Gigabit Ethernet is 1000 Mbps using CAT6 or CAT5e UTP cable and devices.
For both Ethernet and WiFi, The connection speed will always negotiate to the speed of the slowest device.
For example if you have CAT6 Ethernet cable connected to your router which has Gigabit Ethernet (1000 Mbps) ports, and it is connected to a old PC with a 10 Mbps NIC (network interface card) then your connection speed would be limited to 10 Mbps.
In order to achieve Gigabit LAN speeds, all devices in the connection need to be Gigabit. This would include the LAN ports on the router, the network interface cards in both devices and the cables connecting them.
If you are trying to increase Internet performance, you are wasting your time, unless your ISP connection exceeds 1 Gbps.
Here is how it works,
A router connects two separate networks and manages the traffic between them. In most home network applications the router connects your local group of computers and devices known as the LAN with the Internet, commonly called the WAN or Wide Area Network.
The router enables you to connect multiple devices together into a home network (LAN), and share a single ISP (WAN) Internet connection, so all of your devices can access the Internet.
Fast routers and connections such as Gigabit Ethernet are designed to permit fast transfer of data between devices connected to your local LAN. No matter how fast your equipment is, Internet speed is still limited by the speed of your ISP package.
The only way to speed up a Internet connection is to get a faster ISP plan.
Your Internet bandwidth is shared among all of the users of your LAN. So any bandwidth others are using will be deducted from the total Internet (WAN) bandwidth that is available to you.
For example, If you have a 3 Mbps Internet connection and one user is utilizing 2.5 Mbps of the bandwidth to download a file or stream a Netflix movie, that only leaves 0.5 Mbps for all of the rest of the users on the LAN.
In simple terms, the more users you have the more speed will be required.
Most Internet services do not come close to the speeds of modern wireless routers or connections.
Your best bet, for home use would be a single Gigabit Ethernet connection.
Good Luck...