SD-WAN includes that but it is not its sole purpose, although I agree most vendors will say that’s what you want. WAN/Link Aggregation, Multilink Aggregation, Link Load Balancing, Equal Cost Multipath, WAN Virtualisation, etc are ways to bundle multiple links together.
In WIFI terms, it’s called channel bonding, it was proprietary and various vendors had their own implementations, see “Super G”.