envelope

busta

Involucro piatto di carta in cui si mette una lettera o un biglietto, soprattutto per spedirlo.

In inglese semplice: A flat paper cover that holds a letter or card, especially when you send it by post.

• Put the letter in an envelope.
• She wrote my address on the envelope.
• Who sent this empty envelope?

Espressioni comuni: sealed envelope, open an envelope, envelope address, paper envelope

involucro

Strato o rivestimento esterno che circonda completamente qualcosa.

In inglese semplice: A layer or outer cover that surrounds something completely.

• A protective envelope surrounds the cell.
• The balloon’s envelope was filled with hot air.
• The planet has a thin envelope of gas.

Come si usa: an envelope of something (An envelope of hot gas surrounds the star.)

Sinonimi: covering, outer layer

Espressioni comuni: outer envelope, protective envelope, envelope of gas

inviluppo operativo, inviluppo di volo

Limiti entro i quali una macchina o un sistema può funzionare correttamente e in sicurezza.

In inglese semplice: The limits within which a machine or system can work safely and properly.

• The aircraft stayed within its flight envelope.
• Engineers tested the motor’s operating envelope.
• Flying outside the envelope can damage the aircraft.

Come si usa: within/outside the envelope (The pilot kept the aircraft within its flight envelope.)

Sinonimi: operating limits

Espressioni comuni: flight envelope, operating envelope, performance envelope