[elmimmo]

Transformers do not transform but convert in Hasbro’s marketing and licensed materials, and strictly speaking they’re not even supposed to be Transformers but Transformers robots (which grammatically is wrong, but alas). Except, for whatever valid reason, inside the fiction, where Transformers becomes a perfectly valid noun they refer themselves with and they do transform, not convert, all day long. I don’t get it.

[bitwize]

The decision to avoid use of the verb "to transform" is recent (2000s or 2010s), and probably due to legal troubles Hasbro's lawyers don't want to get into again. Recent Transformers media do eschew the usage of "transform" as a verb, preferring "convert" or "change form" instead. The part (organ?) that Cybertronians have that facilitates changing shape also had its name changed, from "transformation cog" in G1 to "conversion cog" in the War for Cybertron game. And Optimus Prime saying "Autobots, transform and roll out!" has gone the way of Mario saying "Yahoo!" (Nintendo feared trademark suits from the internet company Yahoo!).

The funny thing is, back in the days when Transformers transformed, their rivals the GoBots converted.