Ionic compounds are two or more ions held together by attraction. An example of an ionic compound is table salt. It consists of positive sodium ions and negative chloride ions. It is a crystal that can be seen with the naked eye. If it looks like it is a powder it is just because the crystals are too small to actually be seen. They have high melting and boiling points and are hard or brittle. They can also be dissolved in water.
The definition for a non ionic compound is simply means that the chemical bonds are non ionic. They cannot be dissolved in water. They usually have chemical bonds that share electron density.