Initialism of all-terrain vehicle. (an astride-seated quad or tri-wheeled off-road recreational vehicle)
"The muddy trail was perfect for her new red ATV, which she used to race across the forest hills."
In plain English: An ATV is an all-terrain vehicle designed to drive over rough ground with four wheels and handlebars for steering.
"He drove his red ATV through the sandy trail behind our house."
Initialism of Associated Television.
"The ATV station in Mumbai was a prominent broadcaster before it was acquired by Zee TV."