The building blocks of English

Affixes

-logue

In the US usually -log.

A type of communication or debate.

French ‑logue, from Greek ‑logos, ‑logon, word or speech.

Examples include monologue (Greek monos, alone), a long speech by one actor, or a one by someone monopolising a conversation; dialogue (Greek dia, through), a conversation between two or more people or groups, often to resolve some problem; travelogue, a film, book, or illustrated lecture describing travels; epilogue (Greek epi, in addition), a concluding part to a book or play; Decalogue is another name for the Ten Commandments in Christian theology.

In catalogue (Greek katalogos, from katalegein, pick out or enrol), it has the rare sense of a compilation; a few modern formations are based on it, including magalogue, a blend of magazine and catalogue, a promotional catalogue or brochure designed to resemble a high-quality magazine.

Rarely, the ending is equivalent to ‑logist: ideologue.