I think mdocod is probably correct. At the same time, I can't help but think that
sensible (no, this does not include all) manufacturers, dealers and what not, refer to Li-Ion and 3.6-3.7 Volt lithium primary cells by their dimensional name (eg. 14500) to help prevent confusion that could cause accident or injury when someone puts the wrong chemistry cell into the wrong charger, 2 14500 unprotected (or otherwise) LiCo's into a stock Mini-Mag, or whatever.
I have seen cell chemistry other than Li-Ion, or 3.6-3.7 Volt primary lithium, referred to by the numerical dimensional designation. The R/C world, and bulk battery cell distributors, for example, sometimes refer to nickel based cells by their numerical designation. These people are knowledgeable (hopefully) enough with the different chemistries, to build packs and such without risking personal injury to themselves, or their customers.
I can't say I've ever seen the numerical designation used for alkaline AA, C, or D cells, nor the AA, C, or D designation printed on semi consumer 3.7 Volt lithium cells, like Saft, for example, at the consumer level. I would hope this doesn't change. There are some dealers and the like, that do call 3.7 Volt Li-Ion cells "C" or "D". I find this to be a bad practice, even if it is technically correct. The cells themselves, have the numerical designation.
Just a reminder, and mdocod, I know you already know this,
I've seen "16340" cells that are actually a LiFeP04 cell, or a LiMn cell, or a buck regulated LiCo cell, or a standard LiCo cell.
all these cells
are Lithium
Ion cells.
Dave