Were lithium crystals ever actually used in warp drives?

In the earliest episodes of the original Star Trek, the Enterprise’s warp drives are powered by and/or regulated by "lithium", and a maintenance visit is made to the "lithium cracking station" of Delta Vega.

Memory Alpha observes,

According to Star Trek Encyclopedia, originally, lithium was said to be used to control the warp reaction, but it was quickly realized that since lithium was a real element, with known properties, it would not be able to do some of the things the writers wanted it to do.

In the prequel series Enterprise, no mention is made of lithium per se as a substance relevant to warp travel, and ships are apparently already using dilithium (e.g. the ENT episode Affliction explicitly mentions dilithium).

In current Star Trek canon, was crystalline, metallic, or elemental lithium (atomic number three on the periodic table) ever actually used in warp engines? I can see two ways to interpret the use of the term "lithium" in the context of the entire franchise:

• There is a period of time when Earth and/or Federation ships switch from dilithium to lithium and then later back to dilithium again. This could be a temporary measure due to a dilithium shortage, environmental legislation, etc., with lithium used briefly as a stopgap during the period when dilithium is unavailable. This could also represent a failed experiment, with lithium being introduced as a newfangled replacement for aging dilithium tech, only for lithium to be proven too expensive, too dangerous, etc. for continued use, with a project to retrofit lithium-powered Constitution class ships back to the "old" dilithium tech starting up in the mid-Kirk era.
• Earth/Federation ships (at least from the time of the NX-01) have always used dilithium, but some people in the early Kirk era call it "lithium" as a sort of nickname or shorthand, similar to the way many Earth humans today use the term "gas" to refer to a variety of hydrocarbon-based fuels whose exact nature depends on the context of conversation.

I know the out-of-universe reason that "lithium" was dropped from the script. The question is solely about whether this represents an in-universe change in technology (i.e. a brief period of time in which actual lithium is used) or whether the "change" has been retconned as a terminology issue or similar.

In response to an answer by M. A. Golding, it does make sense that the terms "lithium" and "dilithium" are both shortened forms of some longish chemical name. What I’m looking for is actual evidence of this. For example, if there is an early script-writer’s guide that says, "The power matrix of the Enterprise’s engines is regulated by crystals of Tessellated di-Lithium Hydro-argentate, or "lithium" as it is called by the crew.", that would be an excellent answer. If there is an episode where some established characters continue to use the term "lithium" while new characters (e.g. a crystal merchant du jour) call it "dilithium" (e.g. "I understand that you need some high-quality level five dilithium hydrate for your engines, eh.?"), that would also be an answer.