first step

Từ điển WordNet v3.1 - WordNet Dictionary

noun

the first of a series of actions (Freq. 8)
• Syn:
initiative, opening move, opening
• Derivationally related forms:
opening (for: opening), open (for: opening)
• Hypernyms:
beginning, start, commencement
• Hyponyms:
curtain raiser, first base, peace initiative