Classis may refer to:
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Classis (ecclesiastical), governing body of pastors and elders in certain churches
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Classis (biology)
In biological classification, class ( la, classis) is a taxonomic rank, as well as a taxonomic unit, a taxon, in that rank. It is a group of related taxonomic orders. Other well-known ranks in descending order of size are life, domain, kingdom ...
, or class, a taxonomic rank or unit in biology
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Classis (port)
Classe was a commercial port located east south east from Ravenna, Italy. It was near the head of the Adriatic coast. For almost five hundred years it was an important strategic military port. When it was not being used as a military port, it was ...
, or Classe, ancient port of Ravenna, Italy
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Roman classis, fleet of Roman navy
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