This is the 4266th most frequent Russian word.
агентств
The word "агентств" is the genitive plural form of "агентство," meaning "agency" in English (e.g., organization or office offering services).
Here, 'агентствах' is used as a plural form denoting the term 'agencies,' referring to organizations specializing in advertising.
Я работал в нескольких рекламных агентствах за последние пять лет.
I have worked in several advertising agencies over the last five years.
In this sentence, 'агентство' is singular and refers to an organizational entity dedicated to the specific field of space exploration.
Международное агентство по изучению космоса открыло новый проект.
The international agency for space exploration has launched a new project.
The term 'агентств' in this sentence denotes the plural possessive form of agencies, in this context pertaining to those specializing in real estate.