User blog comment:QuantumFeint/Botlane meta - where did all the supports go?/@comment-31656015-20140906131755

Support role is NOT limited to just healing and providing assistive buffs.

Support - Give assistance.

Offensive buffs, crowd control  both have support qualities. the main role of being a support is to provide utility to allies, rather than yourself.

that's the breaking rule between supports and other champions. To be a support, a champion needs to provide a certain measure of utility towards one's team.

Leona / Thresh etc. ARE supports, pure supports.

They end up being "support role TANKS" because poor offensive scaling requires them to build defensive for maximum utility.

These champions, while not providing assistive buffs, instead a geared to providing offensive power to teams. the reason they are proper supports, is because their kits are hard wired to support,  not being optimum elsewhere.

whereas other champions such as Vel'koz / Morg. are secondary supports due to having perfectly fine strength on their own solo lanes, but have kits that provide a reasonable amount of utility to be valued outside a damaging role.

those are the 2 different kind of "supports"