What is meant by concentration gradient,turgor prossure gradient,oxygen gradient?

all three terms have to do with diffusion. Concentration gradient has to do with which way the matter is going to diffuse. tugor pressure has to deal with the amount of water in the vacuole of the plant cell (high tugor pressure causes the plant to stand firm). Basically once the word 'gradient' is attached to a term, it is refering to the tendency of diffusion of matter