There are several types of relationships of interest to a genealogist.
Blood relationships are determined by computing the shared ancestry of two individuals. Typically, people express such relationships using terms that reflect the most direct relationship. That is determined by counting the generations from each individual to the closest common ancestor; siblings share a parent, first cousins share a grandparent, etc.
Consanguinity usually refers to a calculation of shared ancestry that includes all common ancestors.
Most cultures and languages have special terms to describe close blood relationships such as mother, father, parent, child, sibling, aunt, uncle, niece, nephew, and cousin. Those relationships are well-understood and it is not necessary to actually count the generations to know the relationship. Terms in common use for more distant relationships are generally less precise. In English, people who share an ancestor more than two generations back may simply be called cousins or distant cousins. (Source: Encyclopedia of Genealogy)
Kinship or Consanguinity Chart
To find the relationship or consanguinity of two persons, we'll call them A and B, find person A in the row to the right of the common ancestor; then find person B in the column below the common ancestor. Then follow the column of person A down to the box where it intersects with the row of person B.
For example, if A is a grandson or granddaughter of the common ancestor, and B is a great grandson or granddaughter of the common ancestor, the box where their respective column and row intersect tells us that they are first cousins once removed.