IPA: /ˌɪn.əˈsmʌtʃ/
KK: /ɪnəˈsmʌtʃ/
To the extent that; considering the fact that; since.
Inasmuch as it was raining, we decided to stay indoors.
To the extent that; in view of the fact that.
Inasmuch as the weather was bad, we decided to stay indoors.
Inasmuch is formed from "in" (meaning within or inside), "as" (meaning in the same way or to the same degree), and "much" (meaning a large amount or degree). The word combines these parts to express a condition or degree of something, essentially meaning 'to the extent that' or 'considering that'.
Think of being 'within' ('in') a certain degree or 'amount' ('much') of something — that's how inasmuch relates to the extent or condition of a situation.