how do the cross over and non-cross over chromatids differ ? Give alternate terms for them also ?

Chromatid refers to either of the two copies of duplicated chromososme, found linked at centromere and formed during DNA replication.  Chromatids of same chromosome are called sister chromatids, while chromatids of different chromosomes which are homologous chromososmes are called as non sister chromatids.  During the event of crossing over of meiosis,  the segments of chromatids are exchanged between  non sister chromatids  of homologous chromosomes.  


The non sister chromatids of homologous chromosomes between which crossing over occurs are also referred as cross-over chromatids  or recombinant chromatids.

 One chromatid of each homologous chromosomes remains as it is without crossing over and those chromatids are called non-cross over chromatids or non-recombinant chromatids.

 We are providing you an image that can further make the given concept clearer to you.