Font Forum

From Font Properties on the main menu, under the Masters tab, it would be more accurate to call these titles "Metrics for Horizontal Writing Mode" and "Metrics for Vertical Writing Mode". The term 'writing mode' is what is used in both the OpenType and CSS specifications. Layout is a broader term that usually means something different.

The specs were written more than 2 decades ago, so maybe this terminology is outdated, but it does not mention "writing mode":
https://docs.microsoft.com/en-gb/typogr ... /spec/hhea

It would be great of more people provide feedback on this matter.

Erwin,

See
https://docs.microsoft.com/en-us/typogr ... eatures_uz
The term "writing mode" is used in describing the valt, vert, vrt2, and vrtr tags.

However, the OpenType spec is not always consistent. It also uses "Text Direction" and "Layout Direction".
See https://docs.microsoft.com/en-us/typogr ... /spec/base

Since CSS also uses writing mode, I believe it is a better choice. Anyone who wonders what the term means, can find out by googling. I'm not so sure that is the case for Horizontal or Vertical Layout.

I agree that Horizontal Writing Mode and Vertical Writing Mode convey the meaning better than H/V Layout. Horizontal or Vertical Layout could also mean to decide about the position and size of the pictures when you rotate your smart phone.
The text already explains (recommended for fonts that are used for vertical writing)

Great. Consider it done!