IPA: /ˈkæt.əl.ɒ.ɡər/
KK: /ˈkætəlɒɡər/
A person who creates or maintains a list of items, often in a systematic way, such as books or products.
The cataloger organized the library's collection to make it easier for visitors to find books.
Cataloger → It is formed from "catalogue" (from Latin *catalogus*, meaning a list or register) and "-er" (meaning a person who). A cataloger is a person who creates or maintains a list or register of items.
Think of a person who makes a 'list' ('catalogue') of items — that's what a cataloger does.