Definition of overstrike:
(n) :
(computing, uncountable) overtype (feature where input replaces existing characters instead of being inserted before them)
(n) :
(typography) The printing of one character over another, as - on top of L to produce Ł.
(v) :
(transitive) 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.).
(v) :
(transitive) To strike (something) too hard.
(n) :
(numismatics) A coin that has been overstruck, i.e. coined more than once.
(v) :
(obsolete, reflexive) To overreach oneself while striking.