۱، ۲، ۳) سوُمان؛ ۳) دوران ِ سوم
1, 2, 3) sevoman; 3) dowrân-e sevom (#)
1) Third in order, rank, level, stage, formation, etc.
2) Chem.: Being or containing a carbon atom having bonds to three other
3) Geology: (usually with capital initial)
A term formerly used to distinguish a major period of
→ geologic time, from
the end of the → Cretaceous period about 65 million
years ago to the start of the Quaternary period about 1.6 millions years ago.
The International Commission on Stratigraphy no longer sustains this term as part
of the formal stratigraphic nomenclature. Instead, the → Paleogene
and → Neogene periods are
recommended as the primary subdivisions of the Cenozoic era.
From L. tertius, → third;