Wavelength in real life
In real life it means exactly that. If you stand at one point, where there is a peak in that particular wave of wavelength 3.33m (100MHz FM Public Radio Band), then 3.33m ahead of you that exact same wave will have another peak at that exact instant. In between those is the rest of the sinusoidal response.

Because the wave moves at the speed of light, though, you're going to have quite a bit of trouble verifying that accurately just by holding a metal rod and running around.

There's not much more to say about it, really.