wavefront is termed as the locus of all the points joining together woth same phase, a line or curve in 2dimensional
wheras a wavelet is defined as: a wave like oscillation with ampliyude expanding and contracting gradually and sequentially.
						

							
@ sneha 
the locus of all the points of the medium which receives disturbances simoultaneously and are in same state of vibration are called as wavefront . 
every point on a wavefront act as a new source called as secondary wavelets . 
wavelets are just a kind of daughter wave u can say . 
more precisely , wavelets is small wave like oscillation , which starts with zero displacement , increase to max . displacement , then decrease to zero again . 
HOPE IT CLEARS YOUR DOUBT 
ALL THE BEST ..
						

							wave front is a imaginary surface representing corresponding points of a wave that vibrate in same phase for example, a wavefront could be the surface over which the wave has a maximum or a minimum value.             When a wavefront reaches various points of an arbitrary surface ,they act as new sources of light waves emitting spherical waves called secondary wavelets and disturbance beyond the surface results from the superimposition of these secondary wavelets forming an another wavefront.In simple words,a wavefront is the result of superimposition of various wavelets.