The word "ventings" is spelled with a "t" after the "n" because the "ng" sound at the end of the word is pronounced as a single consonant. In IPA phonetic transcription, this sound is written as /ŋ/. This means that the word should be spelled with a "t" after the "n" to indicate that the "ng" sound is pronounced as a single consonant. Ventings is a plural noun that refers to the act or process of venting, or the release of pressure or emotions.
The word "ventings" does not have a specific etymology as it is not listed in most reputable dictionaries. However, based on the structure of the word, it can be inferred that it is derived from the verb "vent", meaning to release or express strong feelings or emotions. The addition of the suffix "-ings" suggests that "ventings" refers to the act of venting or the things that are vented. Nevertheless, it is important to note that "ventings" could be a colloquial term or have limited usage.