envelopes

"My sister used brightly colored envelopes to mail her thank-you notes to her friends. "

"She stacked the envelopes before putting the letters inside. "

"The engineers carefully inspected the airship's envelopes for any leaks before the flight. "

"The light trails from many fireflies, when viewed together, appear to define envelopes that trace the shape of the bushes they surround. "

"The technician studied the envelopes of the radio signals, searching for any sudden changes in amplitude. "

"The synthesizer allows you to adjust the envelopes of the drum sounds, making them short and punchy or long and sustained. "

"The email envelopes contain addressing and security information the system needs to deliver the message, but the recipient only sees the actual email content. "

"The virus has protein envelopes that help it enter cells. "

"The safety envelopes for the new amusement park ride clearly state the maximum height and weight allowed for each passenger. "

"Through the telescope, the comet's envelopes, glowing faintly, expanded as it approached the sun. "

"Because the attack came from multiple directions, the defenders built envelopes around the outer fort, creating additional layers of protection. "