You can alias anything you like (but check that the command you want to use doesn't already exist first: type open should tell you not found) Make a backup of your ~/.bashrc and define the alias:
cp .bashrc .bashrc.bak
nano .bashrc
Add at the end
alias open='xdg-open'
Or if you want to avoid seeing any warnings from the program that is called, discard output with a redirection as suggested by TalkLittle:
alias open='xdg-open &>/dev/null'
source .bashrc
Save and exit, then type source .bashrc to use the alias immediately. The alias will take arguments just like the full command, of course.
open 'https://www.google.com/' or open https://www.google.com/
Opens the freedesktop.org website in the user's default browser.
open /tmp/foobar.png
Opens the PNG image file /tmp/foobar.png in the user's default image viewing application.