The word "Theorematical" is not a valid spelling in English. The correct spelling is "Theoretical" /ˌθiːəˈretɪkəl/. The IPA phonetic transcription for this word is as follows: a voiced dental fricative /ð/ for the first two letters "th"; followed by a long vowel sound /i/ represented by the letter "ee"; then a schwa sound /ə/ for the third syllable; and finally, a voiceless velar plosive /k/ at the end. Therefore, the word "Theoretical" is pronounced as thee-uh-ret-uh-kal.
The word "Theorematical" does not have an established etymology as it is not a commonly used or recognized term in the English language. It appears to be a combination of the words "theorem" and "mathematical" or "theoretical" (or a combination of both). However, without a specific context or origin, it is difficult to determine the exact etymology of this uncommon word.