Meaning of Yamaguchi as a noun

The entrance to a mountain. The gateway to a mountain.
In falconry, the act of first entering the hunting ground to begin the hunt. Also, that location. The entrance to the hunting ground.
The first sign or indication of something.
A woodcutter beginning to fell trees in the mountains.

Yamaguchi as a place

A place name in central Yamaguchi Prefecture. The prefectural capital. An abbreviation for Yamaguchi Prefecture.

A prefecture occupying the westernmost part of Japan’s Chugoku region, facing the Sea of Japan to the north, the Hibiki-nada to the west, and the Seto Inland Sea to the south.

An old village name in Kiso District, southwestern Nagano Prefecture.

One of the surnames

A surname derived from topography. Since it is widely scattered across various regions, it is rarely inherited through specific clans or place names. It is thought to originate from the entrance to a highway passing through mountainous areas, the entrance to a mine, or a settlement at the foot of a mountain.
In Japan, Yamaguchi ranks 14th in frequency, with approximately 600,000 people bearing the surname.

Japanese American Surname Ranking (U.S. Census Bureau, 1990 Survey)

In the Japanese American surname ranking, it is 44th.

1	Tanaka	田中	4th in Japan
2	Yamamoto	山本山元	8th in Japan
3	Nakamura	中村仲村	7th in Japan
4	Watanabe	渡辺渡部・・・	5th in Japan
5	Sato	佐藤	1st in Japan
6	Yamada	山田	12th in Japan
7	Kimura	木村 (written vertically)	17th in Japan
8	Suzuki	鈴木鈴木 (written vertically)	2nd in Japan
9	Kato	加藤	10th in Japan
10	Yoshida	吉田	11th in Japan
11	Takahashi	高橋	3rd in Japan
12	Higa	比嘉	1st in Okinawa, Japan
13	Kobayashi	小林	9th in Japan
14	Nakano	中野仲野・・・	46th in Japan
15	Hayashi	林	20th in Japan
16	Hashimoto	橋本	24th in Japan
17	Saito	斎藤斉藤・・・	19th in Japan
18	Sasaki	佐々木	13th in Japan
19	Mori	森毛利・・・	22th in Japan
20	Matsumoto	松本 (written vertically) 松元	15th in Japan
:
44	Yamaguchi	山口	14th in Japan