This is the 3263rd most frequent Japanese word.
山岸
"山岸" (Yamagishi) is a Japanese surname meaning "mountain edge" or "mountain bank."
In this context, "山岸" is a family name and used to address a person politely with "さん".
山岸さんは昨日新しいプロジェクトを始めました。
Mr./Ms. Yamagishi started a new project yesterday.
Here, "山岸" forms part of "山岸山," referring to a mountain named Yamagishi.
山岸山には美しい花が咲いています。
Beautiful flowers are blooming on Mount Yamagishi.
"山岸" in this sentence refers to the name of a region.