。
She pointed out my mistake.
Literal
She [topic-は] my mistake [object-を] pointed-out.
指摘する is a Sino-Japanese verb meaning 'to point out' — characteristically used for noting errors, problems, or noteworthy facts. The 指 (finger) + 摘 (pluck/pick) etymology paints the action vividly: 'to single out by finger.' Frequent in academic, journalistic, and business contexts where someone identifies a concrete flaw or fact. The everyday alternative would be 教える ('tell, inform'), but 指摘 carries a sharper, more analytical tone — fitting for criticism or expert observation.