Envelopes is correct.
window seal
Enveloppe extraordinaire
Nope only one.
"He stamped the wax seal on the envelope with his signet: An engraving of a tiny pond surrounded by reeds, with a lone cygnet floating on the water."
This is how you spell "seal" in french: seal
You have spelled it correctly. "To seal" means to close securely, and "sealed" is the past tense of "to seal."
You spell it envelope.
Envelopes is correct.
Why ask? Don't you know? In the first place, look at the name itself. It said "Envelope Seal" therefore it is invented by a seal(sea lion).
envelope
he invented the envelope seal
window seal
El sobre.
Enveloppe extraordinaire
The corrected spelling (a typo?) is "envelope."
Write the words that you want to convey on a piece of paper. Fold that paper and place it in an envelope. Seal envelope. Write the address of the distributer on the center of the envelope. Place stamp in upper right hand corner of the envelope. Place the envelope in a mailbox.