thermostad
{{Short description|Homogeneous layer of oceanic waters}}
{{not to be confused with|Thermocline}}
A thermostad is a homogeneous layer of oceanic waters in terms of temperature, it is defined as a relative minimum of the vertical temperature gradient.{{Cite journal|last=Tsuchiya|first=Mizuki|date=1986|title=Thermostads and circulation in the upper layer of the Atlantic Ocean|journal=Progress in Oceanography|volume=16|issue=4|pages=235–267|doi=10.1016/0079-6611(86)90040-6|bibcode=1986PrOce..16..235T}}
The term was coined in 1966 by R. Carlton Seitz, at the time at the Chesapeake Bay Institute of Johns Hopkins University.{{cite web |last1=Michael S. McCartney |title=Subantarctic Mode Water |url=https://www.whoi.edu/science/PO/people/mmccartney/pdfs/McCartney77.pdf |publisher=Woods Hole Oceanographic Institute |location=In: A Voyage of Discovery: George Deacon 70th Anniversary Volume, M. V. Angel, editor, Supplement to Deep-Sea Research, Pergamon Press, Oxford, pp. 103-119. |date=1977}} See [https://www2.whoi.edu/staff/mmccartney/publications/?_gl=1*1difv64*_ga*MTE4NTE1MDIwMy4xNzA0MTE4Mzky*_ga_HLKFZX9JZK*MTcwNDExODM5MS4xLjEuMTcwNDExODgwNS4wLjAuMA..*_gcl_au*MTgwMjQ2MDI1Ni4xNzA0MTE4Mzkx Publications - Dr. Michael S. McCartney].
He proposed it as in opposition to a thermocline, in which the thermal gradient is large. The ending "stad" is from the Greek word στάδην meaning "in an upright position", from the root ἵστημι meaning to stand.{{cite journal |last1=R. Carlton Seitz |title=Thermostad, the Antonym of Thermocline |journal=Journal of Marine Research |date=Dec 25, 1966 |volume=25 |page=203 |url=https://elischolar.library.yale.edu/cgi/viewcontent.cgi?article=2098&context=journal_of_marine_research}}{{cite web |title=στάδην |url=https://morphologia_gr_en.en-academic.com/1211811/%CF%83%CF%84%E1%BD%B1%CE%B4%CE%B7%CE%BD |website=Morphologia Graeca |publisher=en-academic.com}}
The suffix "-stad" is now widely used in oceanography.{{cite news |title=Raymond Carlton Seitz Presented with the Albert Nelson Marquis Lifetime Achievement Award by Marquis Who's Who |url=https://www.24-7pressrelease.com/press-release/460905/raymond-carlton-seitz-presented-with-the-albert-nelson-marquis-lifetime-achievement-award-by-marquis-whos-who |work=24-7 Press Release Newswire |date=Mar 5, 2019}}