The story
From polo + shirt; so called because they were initially modeled on the type of shirt worn from the 1920s by polo players.
Etymology from Wiktionary, CC BY-SA 4.0.
polo shirt
po·lo shirtToday it means: A casual, usually short-sleeved, shirt with a protruding collar and a small number of buttons extending a short distance below the collar (and not all the way down the front of the shirt). Full definition →