pushdown

English

Etymology 1

From push +‎ down; by analogy with a spring-loaded stack of plates in a cafeteria.

Adjective

pushdown (not comparable)

1. (computing) Describing a stack in which items are removed in a LIFO manner from the end at which they were added.

Noun

pushdown (plural pushdowns)

1. A pushdown automaton.
   • 2003, Wilfried Brauer, Hartmut Ehrig, Juhani Karhumäki, Formal and Natural Computing: Essays:

     Since indexed grammars are context-free grammars with pushdowns, the generalization of Thatcher's result shows that they generate the yields of the tree languages recognized by deterministic pushdown tree automata.

Etymology 2

Deverbal from push down.

Noun

pushdown (plural pushdowns)

1. (bodybuilding) An exercise that requires one to push weight downward.
   • (Can we date this quote?), Greg Merritt, “Go Beyond Failure with Dropsets”, in Muscle & Fitness‎^[1]:

     Machine exercises with weight stacks, like pushdowns or pulldowns, are ideal for cranking out more than three drops because all you need to do is insert the pin in a higher (lighter) slot each time.