Displacement is the distance from the equilibrium position in a particular direction. It can have a positive or negative value. The amplitude is the maximum displacement from the equilibrium position. The amplitude is always given as a positive value. 
The wavelength is the minimum distance between two points in phase on adjacent waves e.g. the distance from one peak to the next. The wavelength is measured in metres
The time period of oscillation is the time taken for one complete oscillation or the time taken for one wavelength to move past a given point. 
The time period is measured in seconds. The frequency is the number of wavelengths passing a given point per unit time. The frequency is measured in hertz. The frequency is related to the time period by: f = 1/T. The wave speed is the distance travelled by the wave per unit time. The wave speed is measured in metres per second (ms-1)The Wave EquationThe wave equation states that:v = f λ
Where v is the wave speed, λ is the wavelength and f is the frequency of the wave.
The wavelength is the minimum distance between two points in phase on adjacent waves e.g. the distance from one peak to the next. The wavelength is measured in metresThe time period of oscillation is the time taken for one complete oscillation or the time taken for one wavelength to move past a given point. The time period is measured in seconds. The frequency is the number of wavelengths passing a given point per unit time. The frequency is measured in hertz. The frequency is related to the time period by: f = 1/T. The wave speed is the distance travelled by the wave per unit time. The wave speed is measured in metres per second (ms-1)The Wave EquationThe wave equation states that:v = f λWhere v is the wave speed, λ is the wavelength and f is the frequency of the wave.