point of departure

point of departure (plural points of departure)

1. (travel) Synonym of starting point
   • 2021 January 23, 刘强, “Greater Bay Airlines applies to HKSAR for routes”, in China.org.cn‎:

     […] the point of departure is Hong Kong International Airport.

2. (formal, figuratively) of abstract processes that can be compared to a voyage: initial circumstances. Frequent collocations include, but are not limited to:
   • state of affairs, viewpoints at the beginning of rounds of negotiations or discussions in general

     2021 January 17, Kathija Yassim, “An experiment in what school could be”, in Mail & Guardian‎:

     […] so “going back to the way things were” is not a useful point of departure.

   • set of presumptions in a line of thought, a theory

     2020 January 31, Felix Berenskoetter, “Anxiety, Time, and Agency”, in Forthcoming in International Theory‎, Cambridge University Press, DOI:10.1017/S1752971920000111:

   • separation from a mindset

     2021 January 26, Nayomi Munaweera, “What Kamala Harris means to women who are childfree by choice”, in Vox‎:

     […] choosing to be childfree was a huge point of departure from my community […]

3. (toxicology) a dosage level at which additional administration of an agent significantly loses its efficacy

   Synonym: reference point

   • 2017 April 6, “What Is Point of Departure (POD) and How to Use It to Calculate Toxicological Reference Dose (RfD)”, in ChemSafetyPro‎:

     In toxicology, point of departure (POD) is defined as the point on a toxicological dose-response curve […] generally corresponding to an estimated low effect level or no effect level.

• Reference dose on Wikipedia.Wikipedia
• “point of departure”, in Lexico, Dictionary.com; Oxford University Press, 2019–2022.
• “point of departure”, in Merriam-Webster Online Dictionary
• “point of departure”, in Collins English Dictionary.
• “point of departure” in Longman Dictionary of Contemporary English, Longman.