A lockscreen couple is what you call two
people that share the same lockscreen wallpaper on their smartphone. Usually
annoying overly lovey-dovey couples make a picture together and put it as their lockscreen wallpaper to show everyone their
love.
Dan: "Omg, ur lockscreen is
amazing, I want it."
Lucy: "Here you go! <Sends picture>"
Dan: "Omg, we're a lockscreen couple now. That's bare
dank."
Stranger 1: "Gasp! We have the same lockscreen wallpaper!"
Stranger 2: "Nooo! That means we're a Lockscreen Couple!"