LTE is a proper name for the latest flavour of a wireless connectivity steandard. It simply means ‘long-term evolution’, because naming it after the actual underlying algorithms would be ‘orthogonal frequency-division with multiple access’ was too long even for nerds who created that standard, and also it uses simpler frequency-division with multiple access for transmitting data from your phone to the cell tower, so the actual proper name would be ‘OFDMA uplink FDMA downlink’.
And 5G is still mostly LTE, just with extra radio channels and an optional millimeter frequency support.
There were similarly several 3G technologies - HSDPA, HSPA+, DC-HSDPA, DC-HSDPA w/MIMO, each offering a better speed, but that would be confusing, so the operators just named everything as 3G.