overstrike

Short definition from Wiktionary

Verb

1. 1
   To overreach oneself while striking.
2. 2
   To cover up (a design, mark etc.) by stamping another on top of it; to superimpose a mark or logo on (a coin, stamp, etc.).
3. 3
   To strike (something) too hard.

Noun

1. 1
   A coin that has been overstruck, i.e. coined more than once.
2. 2
   The printing of one character over another, as - on top of L to produce Ł.
3. 3
   overtype (feature where input replaces existing characters instead of being inserted before them)