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notches; serration; indentation; jaggies (stair-step artifacts in computer images)
notched; serrated; jagged; corrugated; milled
「刻々」 has another reading with different meanings.
刻々のナイフは危ない。
A serrated knife is dangerous.
ナイフの刃がぎざぎざになった。
The knife blade got jagged.
紙の端が刻々に切れている。
The edge of the paper is cut jaggedly.