Used when covering something in a broad, non-detailed way: a quick overview, a rough summary, or doing something without going into depth. Often appears as 一通り～する or 一通り～説明する.
ざっと is an adverb meaning 'roughly' or 'briefly', often used with actions like reading or explaining, similar to 一通り but more colloquial.
Etymology
Compound of 一 (ひと, 'one') and 通り (とおり, 'way, passage'). The literal sense of 'one pass through' developed into the figurative meaning of doing something in a single sweep, i.e., roughly or briefly.
