reason, origin, history, oral tradition
謂 centers on the idea of something being said or told, especially to explain why or how something came to be. Its meanings extend naturally from spoken explanation to the reason, origin, or history behind something, and to oral tradition as a body of passed-down sayings.
謂 combines 言 (speech, words) with 胃, which likely contributes the sound. The character originally meant 'to say' or 'to speak of', and from that developed the extended senses of reason, origin, and oral tradition.
Words (言) about the stomach (胃) might be an old story about where food comes from—an oral tradition explaining the origin of a meal. 謂 is the spoken reason or history behind something.
For イ, imagine an eager (イー) storyteller beginning an oral tradition: 'Ee! Let me tell you the reason...' The eager 'Ee!' cues イ.
what is called; what you call; what they call; so-called
what was said; what it means; origin of a story (or tradition, etc.)
reason; cause
unjustified; unwarranted; unfounded; baseless; groundless
origin; history
unjustified; unwarranted; unfounded; baseless; groundless