monomictic
/ˌmɒnə(ʊ)ˈmɪktɪk/Limnology
adjective
Of a lake: having only one seasonal period of free circulation each year.
Origin
1950s; earliest use found in Proceedings of the National Academy of Sciences of the United States of America. From mono- + ancient Greek μικτός + -ic, probably after holomictic, meromictic.