Terminal, Opening Applications Directory
New shells start in your home directory by default, i.e. /Users/username (~). You then specified a relative path to change directory, Applications, which changed directory to /Users/username/Applications.
This is a different folder to the system-wide applications folder at /Applications. When you cd /Applications, the leading slash provides an absolute path rather than relative path, starting at the top of the volume rather than the current working directory (which is your home folder for new shells).