In terms of scale, a universe is significantly larger than a galaxy.
A galaxy is a large gravitationally bound system that consists of stars, stellar remnants, gas, dust, and other celestial objects. Galaxies come in various shapes and sizes, ranging from small dwarf galaxies to large spiral and elliptical galaxies. Our own Milky Way galaxy, for example, contains hundreds of billions of stars.
On the other hand, the universe encompasses everything that exists, including all matter, energy, space, and time. It is a vast expanse that contains billions of galaxies, including our own Milky Way galaxy, as well as countless other structures like galaxy clusters, superclusters, and voids. The observable universe, which is the portion of the universe we can currently observe, is estimated to contain hundreds of billions of galaxies.
So, while a galaxy is a substantial structure in its own right, it is just one of many within the much larger scale of the universe.