For solids, elasticity means the recovery of original shape after stress is gone. What about fluids? They don’t have a fixed volume so is it probably that when the pressure is gone, the liquid recovers its original volume back? If so, then the bulk modulus (the inverse of compressibility) is the elasticity modulus for fluids?
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Liquids have surface tension and are always trying to form a shape with the least surface area. this and cohesion are the closest things to elasticity liquids have since they dont have a defined shape. both of these are pretty weak
There is no single modulus of elasticity for solids. What you’re probably referring to is Young’s modulus, which describes how a solid behaves if it is being stretched in one direction and free to move in the other two directions. But solids also have a bulk modulus, which is another kind of elastic modulus. And they have a shear modulus, which is yet a further kind of elastic modulus. There are even more than these three, in fact.
Fluids aren’t usually talked about as exhibiting elastic behavior in general, because the concept of elasticity is that a material will return to its original shape if a load is removed from it. Fluids don’t return to their original shape after most loads are removed. Only in a very particular case do they do that — that is, when they are being subjected only to isotropic pressure.
You are right that the closest analog to Young’s modulus in a fluid is the bulk modulus, but the bulk modulus is, as I said, actually the exact same thing is the bulk modulus of a solid.
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