steppingstones

/S T EH1 P IH0 NG S T OW1 N Z/
noun
  1. 1

    A stone that can be stepped on in crossing something, especially a marsh or creek.

  2. 2

    Something used as a way to progress to something or somewhere else.

Synonyms

Source: https://en.wiktionary.org/wiki/stepping%20stone, https://en.wiktionary.org/wiki/steppingstone, https://en.wiktionary.org/wiki/steppingstones