Macroscopic things are large enough to be seen without using a microscope. Many creatures, from ants to elephants, are macroscopic.
Macroscopic is the opposite of microscopic, which describes anything you need a microscope to see. A scientist might use macroscopic to talk about the regular view of an object, when you're looking at it unaided by any magnification device. The macroscopic view of a leaf is quite different from the microscopic, which reveals the molecules that comprise it. Macro- means "large," from the Greek root makros, "long or large."