starting line
US /ˈstɑːr.tɪŋ ˌlaɪn/
UK /ˈstɑːr.tɪŋ ˌlaɪn/

1.
the line across a track or course that marks the beginning of a race
:
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All runners gathered at the starting line.
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The referee blew the whistle, and they were off the starting line.
2.
the point at which a new activity or process begins
:
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We're still at the starting line of this complex project.
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For many entrepreneurs, securing initial funding is the real starting line.