GG5: presidency; chairmanship; 〔人〕 a chairman; the chair.
Daijisen: 人々の上に立って全体をまとめること。団体・結社などを、中心となって運営すること。また、その人。

I think shorter and more succinct glosses are better, I'll accept two senses but I don't think there are 3.

@@ -18,3 +18,3 @@
-<gloss>presiding (over)</gloss>
-<gloss>supervision</gloss>
-<gloss>leadership</gloss>
+<gloss>chairmanship</gloss>
+<gloss>presidency</gloss>
+<gloss>management</gloss>
@@ -26 +25,0 @@
-<gloss>leader</gloss>
@@ -28,9 +26,0 @@
-<gloss>chairperson</gloss>
-</sense>
-<sense>
-<pos>&n-suf;</pos>
-<pos>&adj-no;</pos>
-<gloss>run by ...</gloss>
-<gloss>led by ...</gloss>
-<gloss>administered by ...</gloss>
-<gloss>hosted by ...</gloss>

主宰	889866	  
主宰する	169755	  
主宰者	134579	  
主宰の	121912	  
主宰し	119712	

Potential examples of sense [3]:
さん主宰の	14564
氏主宰の		4286
会社主宰の	265
様主宰の		282
自身主宰の	160	

https://eow.alc.co.jp/search?q=主宰
自動
preside
主宰する
preside over（会議・パーティーなどを）

https://context.reverso.net/translation/japanese-english/主宰

presided:
https://context.reverso.net/translation/japanese-english/主宰#presided

https://context.reverso.net/translation/japanese-english/主宰#presiding

https://dictionary.goo.ne.jp/word/en/主宰者/
しゅさいしゃ【主宰者】
the president; the leader；〔会議の〕the chairperson；〔同人誌などの〕the editor (of a periodical)

n-suf usage:
森下さん主宰のダンスカンパニー森下スタンドのダンサーもアシスタントとして参加予定。
Dancers from the Morishita Stand dance company, which Morishita presides over

元モデル主宰の結婚相談所 = Marriage agency run by former model
https://blogmura.com/profiles/10209008/

https://ra.co/dj/mayudepth/biography
run by Japanese techno sound innovator DJ SHUFFLEMASTER
日本テクノサウンドのイノベイターDJ SHUFFLEMASTER主宰の”四季協会”から初のEP

https://ejje.weblio.jp/content/retailer-sponsored+cooperative
retailer-sponsored cooperative
小売業者主宰のコーペラティブ

https://eu-japanfest.org/meet-up/artist/profile/443
鈴木ユキオ主宰のYUKIO SUZUKI projects所属。
And I belong to a dance company run by Yukio Suzuki.

https://prtimes.jp/main/html/rd/p/000000010.000033995.html
2020年大阪府主宰のベンチャー企業育成事業「Booming!5.0」選出。
google translate: In 2020, he was selected for "Booming! 5.0", a venture company development project sponsored by Osaka Prefecture.

Note: sense[1] is nearly 50% verbal, possibly higher. (after subtracting ngrams for 主宰者 and 主宰の, plus some cases of [2] without 者). 

eijiro has one verbal gloss: "preside".   "presided/presiding/presides over" are the most common reverso glosses.

superintendence seems unnatural to me outside of a school context(though I know it has other uses), and I can't imagine preferring something like "the dance school superintended by...".  superintend/superintendence never appear on reverso for this term. "chairman"/"chairperson" appears (rarely), "chairmanship" does not.

主宰 can mean "leader", but it seems like 主宰者 is probably more common:
主宰者は	23649	76.8%
主宰は	7160	23.2%
主宰者に	8487	61.5%
主宰に	5310	38.5%

There is an odd suffix pattern that shows up in the ngrams for 主宰の
主宰の	121912	  
主宰の結婚相談所	5570	  
主宰の劇団	2390	  
主宰の教室	2066	  
主宰の自主レーベル	1258	  
主宰のダンス・スクール	944	  
主宰のメールマガジン	829	
...
(person or organization who operates)主宰の(organization or activity being operated).

For example, every theatre troupe seems to be run by someone or another.  Google news search for "主宰の劇団" returns 119 matches:
児童と共演 記念日祝う 俳優・西村まさ彦さん主宰の劇団：北陸中日新聞Web
google: Theater company led by actor Masahiko Nishimura

劇作家・演出家の前川知大主宰の劇団『イキウメ』 2024年度の公演出演者を募集
google: Ikiume, a theater company led by playwright and director Satoshi Maekawa

Appears for self-run record labels: "主宰の自主レーベル":
http://natrecords.shop-pro.jp/?pid=172560983
Dutch Post-Punk グループがメンバー主宰の自主レーベル Top Hole Records
Top Hole Records, an independent label run by members of the Dutch Post-Punk group

The thing preceding 主宰 can be a non-human entity. "大阪府主宰の" returns a fair number of results. There is one in the refs, and here is another:
https://sanetosaka.com/wp-content/uploads/2021/02/◆★SA・ネットニュース37号記念誌.pdf
委員は大阪府主宰の「シルバーアドバイザー養成講座、世代間交流コース」修了生から、各地域のリーダー達が集まり委員として企画・運営を諮りました。
google:The committee consisted of graduates from the "Silver Advisor Training Course and Intergenerational Exchange Course" sponsored by Osaka Prefecture


There is a counterargument to [3] that it is an abbreviation of "の主宰の", which does occasionally occur online, but compare on google:
"主宰の" site:mainichi.jp (hundreds of matches)
"の主宰の" site:mainichi.jp" (one real match, but with the more complex structure: "草刈民代の主宰のもと", "under the management of...")

So mainichi, at least, appears to *never* use の主宰の for sense [3].

As with mainichi shimbun, on a google book search for "さんの主宰の" the first page of hits are:
さんの主宰のもとに
さんの主宰の下で,
さんの主宰のもとで
田山さんの主宰の下に
さんの主宰の下に
...

"さん主宰の", by contrast, does not need (or allow) の下.


This seems quite a bit different to me than, say, 社長 as a title you can affix to a name. 

Also, it is clearly not a common title(at least for [3]), as it can follow さん, 氏, etc. All googlable:
"社長主宰の"
"クリントン氏主宰の"
"さん主宰の"

Compare：

田中社長	33974	100.0%
田中主宰	0	0.0%

アメリカ元大統領クリントン氏主宰の会議　... Conference hosted by former US President Clinton (google translate)

A similar analysis probably applies to the homonym 主催 (sponsored by ...).

@@ -17,0 +18 @@
+<gloss>presiding (over)</gloss>
@@ -19,2 +20,7 @@
-<gloss>superintendence</gloss>
-<gloss>chairmanship</gloss>
+<gloss>leadership</gloss>
+</sense>
+<sense>
+<pos>&n;</pos>
+<xref type="see" seq="1325490">主宰者</xref>
+<gloss>president</gloss>
+<gloss>leader</gloss>
@@ -21,0 +28,9 @@
+<gloss>chairperson</gloss>
+</sense>
+<sense>
+<pos>&n-suf;</pos>
+<pos>&adj-no;</pos>
+<gloss>run by ...</gloss>
+<gloss>led by ...</gloss>
+<gloss>administered by ...</gloss>
+<gloss>hosted by ...</gloss>

Meikyo vt and vi additions to n,vs entries
-*- via bulkupd.py -*-

@@ -16,0 +17 @@
+<pos>&vt;</pos>

GG5, prog
daijr/s: また、その人.

@@ -17,0 +18 @@
+<gloss>superintendence</gloss>
@@ -18,0 +20 @@
+<gloss>chairman</gloss>