From LightWiki

An item's Pitch can be equated to a person nodding - rotating the head up and down changes its pitch. In LightWave precision is required so a Pitch (or Heading, or Bank) is given in degrees (accurate to two decimal places) around a 360° circle around the X-axis, which in LightWave points straight left and right. 0° and 360° both point along a flat line parallel with the groundplane (-90° points straight up and 90° points straight down). Pitch is represented in LightWave by a green circle surrounding the item.