Remotely = from a remote location = not physically sitting at the computer being accessed.
Any program that allows you to control a computer over a local network or the internet is categorized as a "remote access" program. Some remote access programs just let you see what is on the screen, others let you actually control the computers mouse and keyboard. If you are wondering whether someone has installed a program like that, usually remote access program have an icon on the bottom right of your screen (your task tray, you might need to expand it with the arrow to see all of the icons) and hover your mouse over them and see what each of them is. If there is a suspected program then just right click and hit exit, then uninstall that program from your computer.