Gateway Mode – Nintendo 3DS with the GW3DS hack installed via the Gateway3DS Blue card and the hack activated by going into Settings->Other Settings->Profile->Nintendo DS Profile. This mode is not permanent and the console can be returned to the normal “unchecked” state by entering the DS Mode.
microSD card (also microSDXC) – these are the smaller micro sized SD cards that are used for storing nds and 3ds roms in the Gateway 3DS Blue and Red cartridges. Up to 2GB they are called microSD cards, and all cards 4GB to 32GB are officially called microSDHC where the HC stands for High Capacity. Cards above 32GB in size are called microSDXC – eXtended Capacity.