Here is what is says
Following its two General Discussion Days on violence against children, held in 2000 and 2001, the Committee on the Rights of the Child resolved to issue a series of General Comments concerning eliminating violence against children, of which this is the first. The Committee aims to guide States parties in understanding the provisions of the Convention concerning the protection of children against all forms of violence. This General Comment focuses on corporal punishment and other cruel or degrading forms of punishment, which are currently very widely accepted and practiced forms of violence against children.All well and good - but here is the definition it settled upon
The Committee defines “corporal” or “physical” punishment as any punishment in which physical force is used and intended to cause some degree of pain or discomfort, however light. Most involves hitting (“smacking”, “slapping”, “spanking”) children, with the hand or with an implement – whip, stick, belt, shoe, wooden spoon, etc. But it can also involve, for example, kicking, shaking or throwing children, scratching, pinching, biting, pulling hair or boxing ears, forcing children to stay in uncomfortable positions, burning, scalding or forced ingestion (for example, washing children’s mouths out with soap or forcing them to swallow hot spices). In the view of the Committee, corporal punishment is invariably degrading. In addition, there are other non-physical forms of punishment which are also cruel and degrading and thus incompatible with the Convention. These include, for example, punishment which belittles, humiliates, denigrates, scapegoats, threatens, scares or ridicules the child.So while things like burning or torturing children are understandably prohibited, so are things that could "cause some degree of pain or discomfort, however light" as well as things that might "threaten" or "scare" them.
Little did I know, back in the day, when my Mom was smacking me with a wooden spoon that she was violating my human rights. She'd better apologize, before I report her to the UN.