first cousin once removed

a child of one's first cousin

第一代堂（表）兄弟姐妹的子女

one's parent's first cousin

父母的第一代堂（表）兄弟姐妹

first cousin twice removed

a grandchild of one's first cousin

第一代堂（表）兄弟姐妹的孫子孫女

one's grandparent's first cousin

祖父母的第一代堂（表）兄弟姐妹

second cousin

a child of one's parent's first cousin

第二代堂（表）兄弟姐妹；父母的第一代堂（表）兄弟姐妹的子女

second cousin once removed

a child of one's second cousin

第二代堂（表）兄弟姐妹的子女

one's parent's second cousin

父母的第二代堂（表）兄弟姐妹

third cousin

a child of one's parent's second cousin

第三代堂（表）兄弟姐妹；父母第二代堂（表）兄弟姐妹的子女