A single eyeglass.
Ella usaba una monocula que le daba un aire de sofisticación y misterio.
She wore a monocle that gave her an air of sophistication and mystery.
El uso de una monocula le daba un aire intelectual, que lo hacía destacar entre sus compañeros.
The use of a monocle gave him an intellectual air, making him stand out among his peers.