The phrase "tension band" refers to a device or structure that helps to distribute and redirect force or tension to increase stability and support. Full definition
While seated with good posture, hold a medium - tension band in both hands up above and slightly in front of your head. (verywellfit.com)
For example, a robust general tension band combined with a heavy band offers roughly the same amount of resistance as a power band, but the combination gives you three different levels of assistance (one with the heavy band, one with robust, and one with both bands). (womenshealthandfitness.com.au)
The perfect home gym setup is MUCH cheaper... there's no reason you need anything other than a jump rope, bodyweight exercises, a few dumbbells, stability ball, maybe a few kettlebells (if you want to get fancy), and perhaps high tension bands for some more variety. (truthaboutabs.com)