/ prəˈlɒŋ; NAmE -ˈlɔːŋ; -ˈlɑːŋ/ verb
[ vn ] to make sth last longer
SYN extend :
The operation could prolong his life by two or three years.
Don't prolong the agony (= of not knowing sth) —just tell us who won!
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WORD ORIGIN
late Middle English : from Old French prolonguer , from late Latin prolongare , from pro- forward, onward + longus long.