I have doubt about Stroke and Steam...

 

whether these two things (in attach) are identical, can we call the red line in the letter A steam ?

 

Thanks a lot

It’s tricky and depends on your definition of stem. Many, including our Glossary, define stem as the “main vertical strokes” only. Note that this use has a relation to “stem” as in plant stem or tree stem. 
On the other hand, people might want to talk about the thick vertical and the thick diagonal strokes at the same time, because they are similar. And I’ve certainly seen people use the word stem for both to achieve that. 

What ralf said. Also, in my experience, "stroke" is mostly used when referring to the calligraphic underlying qualities of a glyph (such as contrast, etc.).

Adding to Riccardo's comment on the calligraphic underlying qualities, in calligraphy and palaeography, a stroke can be in any direction. In calligraphy, the 'ductus' of a letter denotes the direction, number and sequence of strokes which combine to create the letter. (Remembering that in calligraphy, letters are literally stroked into being.) This is not practical for taxonomic & anatomic purposes, hence calligraphers and typographers may distinguish between a [horizontal] bar and a [vertical] stem and a [diagonal] stroke. Regardless of how terms appear to be habitually employed by the industry or discipline, it's best to assume the need to define terms and thereafter maintain consistency. This can be formalized, as in a glossary or chart, or informal eg referring to a 'horizontal bar' and thereafter as simply 'bar'.

Vertical stroke, diagonal stroke, horizontal stroke are easy to understand. So why come up with stems, bars and argue wether stems can be diagonal? The same goes for thick or main stroke and thin stroke. One may describe these as stem and hairline – this may seem logical at first sight but there is no generally known ‘stem-related term’ to describe the thin strokes in a sans serif with low stroke contrast. 

On 10/20/2020 at 10:58 AM, ReflexBlueHorror said:

This is not practical for taxonomic & anatomic purposes

My previous post should illustrate that I wonder why the term ‘stroke’ may not be practical for describing letterforms and their typographic qualities.