IPA: /ˌɪndɪˈtɜːrmɪnəbli/
KK: /ɪndɪˈtɜrmɪnəbli/
In a way that cannot be determined or defined clearly.
The outcome of the experiment was indeterminably affected by various factors.
Indeterminably → It is formed from "in-" (meaning not), "determinare" (from Latin, meaning to limit or define), and "-ly" (a suffix used to form adverbs). The word "indeterminably" means in a manner that cannot be defined or limited.
Think of 'not' ('in-') being combined with 'defining' ('determinare') something, which helps you remember that 'indeterminably' refers to something that cannot be clearly defined.