I'm seeking learned opinions.

I think we refer to "beam antennas" that way because they behave like lamps
with reflectors, directing a beam of RF like a beam of light. I don’t know
the historical accuracy of my thinking.

I've built any number of directional antennas, usually yagis but also quads
for HF and VHF and a 20m Moxon. I never asked about the name before today.
How many elements constitute a beam antenna? (ARRL reminds us that even a
single horizontal dipole has some directivity; they seem to use the word
beam only for antennas of two or more elements.)

"Sal"
(KD6VKW)