whats meaning of phase in & phase out?

Theoritically , it represents the position and direction of vibration  of particle in shm. 

For example, assume a particle oscillating about the origin along x- axis, with x = -5 to x = +5 . where is the particle right

 now ?

the answer is  provided by the quantity called phase angle or phase .

if  2 particles are at the same location x= +3 and both are moving towards right or left, they are in phase

if one is toleft and the other is to right at the same time , ther are out of phase.