This is the 3577th most frequent Japanese word.
谷口
"谷口" (Taniguchi) means "valley entrance" or is used as a Japanese surname.
In this sentence, '谷口' is used as the surname of a person.
谷口さんは優しい人です。
Mr. Taniguchi is a kind person.
Here, '谷口' refers to the geographical term meaning the entrance of a valley.
その家は谷口にあります。
That house is located at the entrance of the valley.
In this sentence, '谷口' is referred to as a name or word in general.