The term "electrostatic" is used with reference to a phenomenon that occurs due to charges which are static or not in motion.
When materials that do not conduct electricity rub against each other, electrons from one of the materials are transferred to the other resulting in a net positive charge on the material that lost electrons and a net negative charge on the material that acquired the electrons.
The charge that is generated due to this process creates forces of attraction which is known as electrostatic attraction. There is also an electric field generated due to the charge.
Some common materials that get electrically charged include wool, amber, plastic, etc. The most widely seen electrostatic phenomenon is lightning.