The word "Oblongum" is spelled with the letters O-B-L-O-N-G-U-M. In terms of phonetic transcription using the International Phonetic Alphabet (IPA), it can be written as /əˈblɒŋɡəm/ or "uh-BLON-gum". The stressed syllable is the second one, with a short "o" sound followed by a consonant cluster "bl" and "ng". The last syllable has a schwa sound followed by a voiced "m" consonant. Overall, the word has a slightly formal or technical feel, and is often used in descriptions of geometric shapes such as rectangles or squares.
There doesn't appear to be a widely recognized word "oblongum" in the English language, so it's difficult to provide a specific etymology. However, it is important to note that adding the suffix "-um" to a noun is often used to create a neuter noun form in Latin or to make it sound more Latin-like. If "oblongum" were a word, it could potentially be derived from the Latin word "oblongus", meaning "elongated" or "rectangular". This hypothesis is based on the suffix "-um" and the fact that "oblongus" describes a shape that is longer in one direction than in the other, just as the term "oblong" does in English.