Sentence:  Owners and sponsors of the <WSD>drive-ins</WSD> feel that in three-quarters of their patrons they have tapped a practically prehistoric strain of human—the hitherto non-movie-goer. 
Meaning of the word marked with <WSD> tags:  An outdoor cinema where movies are projected onto a large screen and patrons watch from inside their vehicles, listening either by a speaker or a designated radio frequency.