I was wrong; it's not really a gerund.

I copy/pasted "adj" from the oxford entry, which had the the example "established and emerging artists".  My own intuition was that "emerging" had a couple of grammatical interpretations, but that I would only actually use "emerging" in an [adj] context in English.  For instance, in my purely [n] example, I wouldn't say "predict the emerging of new markets". (Though you could, and google returns some examples, though rare vs. emergence).

I think "emerging" is a gerund/gerundive.

daijs:
新しい物事が、内部で動き始めること。また、内部の動きが表面化し始めること。独立の気運が胎動する

sankoku:
内部の動きが、表面にすこしあらわれてくる

emerging (adj)
becoming apparent or prominent. <-- almost the literal kokugo definition of 胎動: 表面化し始める

emergence <-- "emerging" is better, but it's an adjective
the process of coming into existence or prominence.
"the emergence of the environmental movement"

A random Japanese-company bilingual powerpoint. Stage 2: moving/developing online games (vs. currently offline offerings).
https://www.capcom.co.jp/ir/data/pdf/fy2004a.pdf
オンラインゲーム市場の胎動 
Moving toward on-line game software market

I don't think what GG5 has is wrong, but I think something has been missed.

No objection to keeping everything in this entry,  but I can say that 胎動する's meaning in context was *very* difficult to interpret(and then have any confidence in) with the current glosses. That's why I put in so much effort.  How do you make "signs of" a verb/adjective.  Or "indications"?  

"stirrings" is straightforward, but it seemed like the wrong word most of the time(in the する case at least, maybe alright as a noun).

For example, what would one do with the daijs example sentence:
独立の気運が胎動する

The daijs example was coincidentally also on wikipedia, on the rise of the Czech independence movement:
チェコ民族独立の気運が胎動する時代にあって、
(google glosses as "national independence was gaining momentum", but I'm also suspicious of google's handling of this term)

Here's one example from a 2021 gov. publication on steps towards carbon neutrality:
https://www.meti.go.jp/shingikai/energy_environment/carbon_neutral_jitsugen/pdf/20210825_2.pdf
3. カーボンニュートラルを目指し胎動する市場の力を活用すること。

I can't see how the previous glosses handle: 胎動する市場の力

And one more strictly-noun usage:
https://www.pentasecurity.co.jp/security_column/未来自動車の変化する５つの要素ー最終回/
新しいサービスによる新規市場の胎動を予測する一方で

In "胎動を予測する", I don't see what could be "predicted" besides "development" or "emergence" of new markets... 

I'm not always sure what the goal of [form] is.  胎動[2] is probably readily understood, but I'm not sure it's a commonly spoken form(If you're familiar with it as such, I'll take your word for it). Where I've found it online, it's in news articles and research papers, not personal blog posts. (By this logic "emergence" in English might be [form], I'm not sure if that's the goal or not).

@@ -30,0 +31,2 @@
+<gloss>emergence</gloss>
+<gloss>(initial) rise (e.g. of a political movement)</gloss>

GG5: 2. 〔新しい動き〕 signs [indications] 《of forthcoming activities》; fomentation.
中辞典: 2. 〈徴候〉 signs; indications

Despite Sankoku, I don't think sense 2 it "formal or literary". It's just regular language.

@@ -28,3 +27,0 @@
-<xref type="see" seq="2858758">胎動する</xref>
-<xref type="see" seq="2858758">胎動する</xref>
-<misc>&form;</misc>