The word chiral ( a Greek word meaning hand) is used for those objects which have right handed and left handed forms, i.e., the molecule which have "handedness" and the general property of handedness is termed as chirality. an object is non-superimposable upon its mirror image is chiral.
three terms are used to designate e.g., a carbon atom bonded tetrahedrally to four different substituents in a chiral molecule: asymmetric carbon, chiral center or stereocenter.
stereogenic center or stereocenter:
It is an atom having a group of such nature that an interchange of any two groups will produce a stereoisomer. All stereocenters may not be tetrahedral, thus a carbon atom of cis- and trans -2-butene provide an example of trigonal planner stereocenter since an exchange of groups at either atom leads to a stereoisomer (diastereomer).
All chiral centers(tetrahedral) are stereocenters but all stereocenters [tetrahedral and trigonal planer (cis-trans)] are not chiral centers.