a. Surrounding, or travelling around the moon
Usage examples of "circumlunar".
They've fired off two unmanned circumlunar Soyuz shots and brought them back to Earth.
Just prior to his arrival at the circumlunar station, the copilot of the Muir had handed Nathaniel a stellarfax.
We got a squawk from the radio-astronomers on the far side because our circumlunar orbit was getting in the way of their dishes every time we came around.
But the radiophotos from last month's Russian circumlunar rocket take in an area of at least seven million three hundred thousand square miles of lunar surface alone.