1. The problem statement, all variables and given/known data I was taught that a crest is the section of the wave above rest position. 2. Relevant equations 3. The attempt at a solution Now that I am studying Physics at higher level I am getting mixed up as sometimes I encounter situations where a crest is the whole part/section of the wave above rest position but in other cases it is refered to as the highest point of the wave above rest position. So my question is... is a crest a whole section above rest position or just the highest point above it?