A computer monitor that is taller than it is wide. Most portrait monitors are actually landscape monitors that can be swiveled into a portrait orientation. See landscape monitor and portrait.
"portrait monitor." YourDictionary, n.d. Web. 06 June 2018. <http://www.yourdictionary.com/portrait-monitor>.
portrait monitor. (n.d.). Retrieved June 06th, 2018, from http://www.yourdictionary.com/portrait-monitor