Sweater tights, socktights, sockpants, and other footed tights that can be worn as pants.
http://www.18onlygirlsblog.com/it-matches-perfectly/
http://www.thecandidforum.com/spandex-leggings-yoga-pants-pictures/23098-her-sweater-isnt-long-enough-footed-tights-pants.html