What does a crossed vee symbol mean?

Depending upon which symbol you mean, it usually means that symbol DOUBLED.

XY is the male chromosomes, i dont know what the symbols for craziness are though

Speech marks, many writers use this: ' Although technically those are speech marks.

It mean like a . Or , or. ? Or ! Or ' that what it means

The symbol on the periodic table means the abrevitation of the chemical element. For example, the chemical element symbol Pm stands for Promethium.