What is the correct spelling for words ending with an element derived from the Greek suffix logos, meaning “to speak”? For example, should one refer to an analog, or to an analogue? This post lists and defines words ending in –logue or –log (with prefixes defined and various inflections provided) and provides more detail below the list about which form to use.
The first spelling when more than one is shown is the prevailing one; the alternative may appear occasionally but is in most cases not considered standard.
1. analogue/analog (“according to”): comparable but different in form and/or function (analogist, analogously, analogousness, analogy)
2. apologue (“away from”): an allegory that offers a moral (apologist, apology, though these words apply to usage for which apologue is not applied)
3. catalog/catalogue (“completely”): a list or register, often with details, or a publication that consists of a list (often of products for sale) with details provided (cataloger/cataloguer, cataloging/cataloguing)
4. dialogue/dialog (“two”): a conversation between two people, an information exchange between a person and a device, or an exchange of ideas and/or opinions, or the written representation of a conversation, the whole of conversational elements of a composition (whether written, recorded, or performed live), or a musical composition comparable to conversation
5. duologue (“two”): a conversation between two people
6. epilogue/epilog (“in addition”): a concluding element of a composition
7. homologue/homolog (“same”): something comparable or similar, or compatible (homologous)
8. ideologue/idealogue (“idea”): someone who uncritically adheres to or advocates a concept or theory
9. monologue/monolog (“one”): a speech by a character in a dramatic performance, a short solo dramatic performance, a comparable written composition, or a comic’s routine, or an excessively long speech during a conversation (monologuist/monologist)
10. prologue/prolog (“before”): an introductory speech in a play (or the actor performing it) or an introduction in a literary work, or a development or event that introduces or precedes another
11. Sinologue (“China”): a student of Chinese culture and history (Sinological, Sinologist)
12. travelogue/travelog (“journey”): a composition or lecture about travel, or a narrated film about travel
For most of these terms, as shown, the –logue form still prevails, though the shorter alternative to a couple of these words is preferred in American English. Analog, however, is generally used only in contexts concerning electronics, as when a mechanical device is distinguished from a digital one (such as in reference to an analog clock); in the sense of “comparative,” analogue is still more common. Catalog is the only word on this list for which the shorter version is the dominant form for all senses. In some cases, spelling ending in –log is not seen at all. (In British English, the truncated form of any of these words is rare.)