Zacharias Janssen. Related items. Optical microscope Electron microscope. 18th century microscopes from the Musée des Arts et Métiers, Paris. A microscope (from the Ancient Greek: μικρός, mikrós, "small" and σκοπεῖν, skopeîn, "to look" or "see") is an instrument used to see objects that are too small for the naked eye.