In politics, a platform refers to the core beliefs and stances on various issues held by a political party.
Each individual stance mentioned in a platform is called a plank. A specific topic may (and often does) have several planks devoted to it. For example, on the topic of abortion, general opposition to abortion (except in limited circumstances, such as to save the mother's life) would be one plank, while opposition to Federal funding of Planned Parenthood would be another plank.