涂改

Often appears in formal contexts where altering text is forbidden - exam answer sheets, legal documents, accounting books - and so 涂改 frequently has a faintly suspicious or rule-breaking flavor. The dedicated product 涂改液 (túgǎiyè, correction fluid / White-Out) is built from this word.

memory

涂 (tú, to smear / paint over) + 改 (gǎi, to change). Literally 'paint-over and change' - exactly what you do with a pen stroke through a wrong word, or a dab of correction fluid.