blood status

Pure Blood:

A witch or wizard of pure wizarding ancestry, without any muggle ancestors whatsoever as far as can be determined.

Pure blood families:

Black family (Died out with the death of Sirius)

Crouch family (Died out with death of Barty Crouch Sr. and Jr.)

Lestrange family

Longbottom family (Neville)

Malfoy family (Lucius and Draco)

Weasley family

Half blood:

A witch or wizard with at least oe wizarding parent, and at least on muggle parent or grandparent.

Half Bloods:

Harry Potter, Tom Riddle, Seamus Finnegan, Nymphadora Tonks, Dean Thomas, Rubeus Hagrid

Muggle born:

Wizarding person born of two muggle parents

Muggle Borns:

Colin and Dennis Creevey, Lily Evans, Justin Finch-Fletchly, Ted Tonks, Hermione Granger

blood traitor:

A pure blood who doesn't insist on maintaing his or her purity.

Sirius was referred to one by his parents.

squib:

A non-magic person born of wizarding parents, a much rarer phenomenon than a muggle born witch orwizard.

Squibs:

Argus Filch, Arabella Figg