The verb "prolong" comes from the late Latin word prolongare, meaning "to lengthen" or "extend".   It is formed from the late Latin prefix pro- ("forward," "forth") and the late Latin adjective longus ("long"), directly reflecting its meaning of making something last longer or stretch out.  It was introduced during the late Middle English period via the Old French prolonguer. 

According to the Oxford English Dictionary (OED), the verb prolong was first used in English around 1425. The OED cites poet John Lydgate as the author of the earliest evidence for the word. 

Examples of "prolong" used in a sentence:  
"Additives are used to prolong the shelf life of packaged food." 
"High interest rates were prolonging the recession." 
"The drug that was meant to prolong her life was determined to have caused her death." 
"He's been in prison for 40 years and doesn't want to prolong the inevitable."  
"You go ahead and give up smoking or drinking or eating fat to try to prolong your life." 
"There is a big question for society about how much we want to spend on expensive drugs to prolong life." 
"You prolong the agony in the name of love." 

45 minutes ago, drpaladin said:

For every prolong should there be a matching antilong?

I had an Auntie Phyllis Long once.  She'd married Fred Long, but only after prolonging the wedding date for three years. 

Just the facts:

PROLONG Definition & Meaning - Merriam-Webster

PROLONG Synonyms: 25 Similar and Opposite Words | Merriam-Webster Thesaurus

PROLONGED Synonyms: 64 Similar and Opposite Words | Merriam-Webster Thesaurus