Think of macro as a lens ability to reproduce a subject life-size on the image sensor--that is, the size of an object is exactly how much space it will take up on the physical area of the sensor surface. Life-size would be 1:1, half life-size would be 1:2, quarter life-size would be 1:4, etc... and remember that these measures are in area, not linear distance.

True 1:1 macro lenses are usually prime lenses with a single focal length, though many of them appear to "zoom" in actual use, while they are merely focusing. If you had two identical cameras and a 1:1 macro lens, you could take a picture of the image sensor of the other camera and focus so closely that the other sensor would fill up the image frame. Some prime macro lenses will have less magnification, as little as 1:2, and some will have more, up to 5:1 (5x) or more.

When a zoom lens offers "macro" ability, what the manufacturer means is that they have designed the lens to be able to focus on objects fairly closely, closely enough to be competitive against competitors zooms, but they might only offer a magnification ratio of around 1:4. This maximum magnification ratio might only be available at one focal length in the zoom range. Starting out, this might be all you need, but don't expect to fill the frame with a lady bug using a zoom lens.

That's what I do in everyday life, but sometimes taking pictures takes you to tricky places. An experience I don't recommend if you're very short sighted is losing your glasses among the heather in a peat bog. Without my glasses, I had to feel my way around to recover them. Thank goodness I did, as they're expensive varifocals. I suppose if I'd lost them for good I could have got around by looking though the camera's viewfinder until I got home and was able to order another pair.