Wave
A wave is a disturbance that transfers energy between two locations without transferring matter between them. AP Physics 2 models it as continuous and periodic, with a well defined wavelength and frequency.
One sentence carries the whole idea, and the CED keeps returning to it. Essential knowledge 14.1.A.1: waves transfer energy between two locations without transferring matter between those locations.
Energy moves, the medium does not. Each particle of the medium oscillates about its own equilibrium position and stays there. A cork on the water bobs up and down while the wave crosses the pond; the cork does not arrive at the far shore. Everything else about waves is bookkeeping on top of that.
The model has a shape. EK 14.1.A.1.ii: a wave is modelled as a continuous, periodic disturbance with well defined wavelength and frequency. That is what separates it from a wave pulse, which is a single disturbance and has neither.
Two ways to feed it more energy. EK 14.1.A.6.iii says the energy a wave carries increases with increasing amplitude, and EK 14.2.A.1.iv says the energy increases with increasing frequency. Both are stated qualitatively, with no energy formula printed.
Where waves are examined. Unit 14 of AP Physics 2. The current AP Physics 1 framework runs from kinematics through fluids with no waves unit, so a waves question on that exam is off syllabus.
From here the tree splits twice: by what the wave needs, into mechanical and electromagnetic; and by which way the disturbance points, into transverse and longitudinal.