Best Answer:  they are opposites... 

RCOOH + R1COH + H+ ---> RCOOCR1 

RCOOCR1 + OH- (usually NaOH) ---> RCOONa + R1COH 

so esterification uses catalytic acid, acid and alcohol to make esters 
saponification uses at least 1 equivalent sodium hydroxide (or KOH) to make acid salt, alcohol 

so they are opposites of a single reaction forwards is esterification; backwards is saponification. 

why is it called saponfication? Because when the ester group is long and large you (like glyceryl tristearate) end up with SOAP:) which is sodium salt of long chain acids (like sodium stearate)
Source(s):ph.d. organic chemist