The Collaborative International Dictionary
                    planoconvex
                    
                        
                
                                                                    bulging \bulging\ adj.
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curving or bulging outward. Opposite of concave. [Narrower terms: biconvex, convexo-convex, lenticular, lentiform; broken-backed, hogged; convexo-concave; gibbous, gibbose; planoconvex] Also See: protrusive. Syn: convex. 
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curving outward. Syn: bellied, bellying, bulbous, bulgy, protuberant. 
Wiktionary
                    planoconvex
                    
                        
                
                                                                    a. (context optics of a lens English) Having one side plane and the other convex
WordNet
                    planoconvex
                    
                        
                
                                                                    adj. flat on one side and convex on the other