When I was a kid, Nissan and Toyota sold pickup trucks without names. I’m not kidding about this. Both Nissan and Toyota offered compact trucks — which sold in vast numbers — with no discernible name. Both automakers simply called their vehicle the "truck," with "truck" in lower case, because it wasn’t a proper name. The Nissan truck and the Toyota truck. These were actual vehicles.
The basic gist is this: back in the 1980s, Nissan and Toyota entered the pickup truck market here in North America, and the simple truth is that trucks were just really different then. There was none of this "luxury truck" stuff, and few people bought pickup trucks unless they truly needed the capabilities of a pickup truck. Four-door pickups didn’t really exist for people to haul around their families, and trucks had no frills. If you had a truck, you needed a truck.
The result was that trucks didn’t really need that much "cool" marketing. If you manufactured a pickup, you could basically sell it off its capabilities (in the case of full-size pickups) or its reliability (in the case of these smaller trucks from Nissan and Toyota) and nobody really went to buy a truck on the basis that it was cooler than any other truck. This, of course, is the polar opposite of today’s world with the Tacoma TRD Pro, the Ford F-150 Raptor and the Chevrolet Colorado ZR2 and on and on and on.
But it was true back then — and the result was that Nissan and Toyota just didn’t throw that much energy into marketing their trucks and making them seem cool. And the result of that was that Nissan and Toyota just didn’t really see a need to name their trucks. And, so, they didn’t: the Nissan truck was just the Nissan truck, though somehow it earned the nickname "Nissan Hardbody" in some circles. In some foreign markets, it was already starting to be called the Navara — a name that has stuck around globally ever since. The Toyota truck, which was called the HiLux in some markets, was never called that in North America. Just the Toyota 4×4 or 4×2, depending on which one you got.
Of course, as trucks started to become more common with a larger demographic, automakers realized the value in naming them — and especially naming them with an appealing, off-roader-seeming, "go-anywhere"-type name that make the trucks seem capable and desirable. The Toyota Tacoma was officially named as such for the 1995 model year, while the Nissan Frontier came out for 1998. Not long after, other trucks that had been given commercial-grade names — the S-10 and the C/K1500 come to mind — were also renamed for better marketing purposes.
But while those trucks at least had alphanumeric names, the Toyota and the Nissan never did — they were just the "truck." It’s hard to imagine now, but it was the way of the world back then.