"A cousin in English kinship terminology is a relative with whom one shares a common ancestor, but in modern usage the term is rarely used when referring to a relative in one's own line of descent, nor where there is a more specific term to describe the relationship, e.g., brother, sister, aunt, uncle. The term blood relative can be used synonymously, and underlines the existence of a genetic link.
"A system of degrees and removes is used to describe the relationship between the two cousins and the ancestor they have in common. The degree (first, second, third cousin, etc.) indicates the minimum number of generations between either cousin and the nearest common ancestor; the remove (once removed, twice removed, etc.) indicates the number of generations, if any, separating the two cousins from each other.
"For example, a person with whom you share a grandparent is your first cousin; someone with whom you share a great-grandparent is a second cousin. Where your relationship to the nearest common ancestor is different from your cousin's relationship then the term "removed" is used to indicate this, for example the child of your first cousin is your first cousin once removed because there is a generation between you.
"Non-genealogical usage often eliminates the degrees and removes, and refers to people with common ancestors merely as cousins or distant cousins."
"This family tree shows the relationship of each person to the orange person. Cousins are colored green, while the grey and blue stripes signify different generations. Note that the term great uncle/aunt or nephew/niece is often used in place of grand uncle, etc., with an additional prefixed great for each generation back; e.g. great great uncle is a synonym of great grand uncle."
Wikipedia, The Free Encyclopidia, http://en.wikipedia.org/wiki/Cousin_chart