Definitions

1. noun

A type of rare or obscure word, especially one that is considered to be of little or no use in everyday language.

“The linguist spent years studying athericeras, hoping to revive their usage in modern language.”

2. adjective

Rare or obscure, especially in a way that is considered to be of little or no use.

“The writer’s athericeral vocabulary made it difficult for the common reader to understand her work.”