Quite true, although I never encountered it in the real world in connection with 2-way radio or television receiving apparatus. But yes, the term is fundamental in telephone technology, for example, and it simply means a passive device with one input with two or more outputs, or vice-versa--"hybrid coil" being the common usage.
However, back to the original suggestion that brought this up: using a "hybrid" as a two-input, one-output combiner to merge two television antennas into one downlead: you'd have to accept the loss through the combiner (and why would you want to?), and cope with any additional signal degradation caused by two active antennas being physically close to each other. You'd also have to ensure that the two downleads from the antennas to the combiner were exactly the same length, to avoid phase distortion--which means putting the antennas at exactly the same elevation on the mast, and that's tough to do.
Bottom line: the hybrid idea in this circumstance is basically okay in theory but it would fail the test of practicality for most installations. The A-B switch is far simpler and problem-free, and the rotor is simpler still. Bonus with the rotor: the $$ you save in not running RG-6 from a 2nd antenna will help pay for the rotor.