Lateral inversion

Lateral inversion is the left-right flip a mirror produces in an image — your right hand appears to be the left hand of your reflection.

• Lateral inversion isn't unique to plane mirrors — it shows up in the images formed by concave and convex mirrors too, alongside whatever other changes those curved mirrors make to size or orientation.
• It's easy to notice lateral inversion by holding up a page of text to a mirror: the letters appear reversed left-to-right, even though nothing has flipped top-to-bottom.
• This effect is exactly why ambulances often print "AMBULANCE" backwards on the front of the vehicle — so it reads correctly when seen laterally inverted in another driver's rear-view mirror.
• Lateral inversion is a property of how mirrors reflect light, not of the curvature of the mirror — which is why it appears consistently across plane, concave, and convex mirrors alike, even while other properties of the image change.