Elucidate
Etymology
From Late Latin elucidare, "to make clear," from ex- ("out, thoroughly") plus lucidus, "bright, clear," which traces to lux, "light," and lucere, "to shine." The metaphor is literally one of shining light out onto a subject — the mirror image of obfuscate, which darkens it.
verb · /ih-LOO-sih-dayt/
To make something clear by explaining it fully.
What it names
The exact verb for shedding light on a difficult point — not just answering but illuminating, so the whole thing suddenly reads as obvious.
Example
A good teacher can elucidate in one sentence what the textbook fumbled across an entire chapter.
Related idea
Explicate means to unfold a text or argument point by point; elucidate is broader — any act that makes an obscure thing clear.