Knowledgeable stair builders, what is this called?

CalypsoArt

Knowledgeable architects or stair builders. What is this called? I've looked in all my resources. I can find no name. I went with Reverse Finial.

TIG

It's on the bottom of a newel post: so include that in its name.
That newel is also extended downwards [aka dropped?]: so perhaps somehow include that in its name.
It's also a cap [or finial]: so include that in its name.

I'd call it a "dropped-newel-with-cap" [or "...[-bottom]-finial"]
[at least in UK-England]

Different locales will probably have different naming conventions...
Draw it and explain in words.
The builder/joiner should understand you...

TIG

Remember that a simple 'dropped-newel' might not have any 'cap' at all [perhaps just chamfers to its exposed edges], so for-the-avoidance-of-doubt I'd add something like '...-with-cap' [or '-finial' etc] if it has one...

S Shepherd

I think I'd go with Dropped Newel.
[Edit] Also pendant might be applicable
S.

rtd

Are you creating design or construction documents?

I assume that there would be a drawing of it at a suitable scale to establish the profile desired. I'd go with 'dropped newel, see detail'.

pmolson

Thingamajig

boofredlay

You could describe it as a dropped or lowered newel post. I have seen it as just a newel post with lower post cap. And if it has a cap at the top then call that out too.

Although Ron describes them as "dropped" on this blog post:
http://stairman.blogspot.com/2015/02/historic-fraternity-house-reproduction.html

Here it is referred to as a newel drop.

CalypsoArt

Thanks all. I'm going with Dropped newel and reverse finial.