A colloid (also known as colloidal dispersion) may look like a homogenous mixture because the mixture looks very uniform. Under a bit of magnification, the solute is not completely dissolved, and the particles are big enough, making the entire mixture cloudy. For example, Mayonnaise is a mixture of egg yolk, vinegar, and lemon juice. It is whisked smoothly to a degree that it feels so smooth, but under a microscope, the solute is not completely dissolved. Examples of colloids are Milk, Mayonnaise, Butter, and Egg Whites.

What is the difference between a colloid and an emulsion?

With colloids, the mixture has components that tend not to settle out when left undisturbed. In addition to that, a colloid involves the uniform dispersion of fine solid particles in a liquid medium.

An emulsion is a uniform mix of two immiscible liquids (immiscible liquids are those that do not dissolve well into each other)