cnv中的v是体积

体积，几何学专业术语。当物体占据的空间是三维空间时，所占空间的大小叫做该物体的体积。

拷贝数变异简称CNV，是指在人群中，基因组特定区域发 生重复、缺失或者拷贝次数改变的现象，涉及范围一般在lkb以上

中文意思是Copy number variations，基因拷贝数变异

There is a wide variation in the amount of these CNV deletions which people have in their genome, with some people having several million.