noun🔗Share信封 A paper or cardboard wrapper used to enclose small, flat items, especially letters, for mailing."My sister used brightly colored envelopes to mail her thank-you notes to her friends. "我妹妹用颜色鲜艳的信封给她的朋友们寄感谢信。stationerycommunicationChat with AIVocabulary GamePractice Reading
noun🔗Share信封，封套。 Something that envelops; a wrapping."She stacked the envelopes before putting the letters inside. "她把信封叠好，然后才把信放进去。stationerymaterialChat with AIVocabulary GamePractice Reading
noun🔗Share气囊，封套 A bag containing the lifting gas of a balloon or airship; fabric that encloses the gas-bags of an airship."The engineers carefully inspected the airship's envelopes for any leaks before the flight. "工程师们在飞行前仔细检查了飞艇的气囊封套，以确保没有泄漏。vehiclenauticaltechnicalmachinepartChat with AIVocabulary GamePractice Reading
noun🔗Share包络，封包，包迹。 A mathematical curve, surface, or higher-dimensional object that is the tangent to a given family of lines, curves, surfaces, or higher-dimensional objects."The light trails from many fireflies, when viewed together, appear to define envelopes that trace the shape of the bushes they surround. "许多萤火虫的光线轨迹，如果一起观察，似乎定义了包络，勾勒出它们周围灌木丛的形状。mathtechnicalChat with AIVocabulary GamePractice Reading
noun🔗Share包络线，包迹 A curve that bounds another curve or set of curves, as the modulation envelope of an amplitude-modulated carrier wave in electronics."The technician studied the envelopes of the radio signals, searching for any sudden changes in amplitude. "技术员研究无线电信号的包络线，寻找任何幅度上的突变。electronicstechnologyphysicsmathtechnicalsignalChat with AIVocabulary GamePractice Reading
noun🔗Share包络 The shape of a sound, which may be controlled by a synthesizer or sampler."The synthesizer allows you to adjust the envelopes of the drum sounds, making them short and punchy or long and sustained. "合成器允许你调整鼓声音的包络，让它们变得短促有力，或者悠长延绵。musicsoundelectronicstechnologysignalChat with AIVocabulary GamePractice Reading
noun🔗Share信封。 The information used for routing a message that is transmitted with the message but not part of its contents."The email envelopes contain addressing and security information the system needs to deliver the message, but the recipient only sees the actual email content. "电子邮件的信封包含了系统投递邮件所需的地址和安全信息，但收件人只能看到邮件的实际内容。communicationtechnologyinternetcomputingsignalChat with AIVocabulary GamePractice Reading
noun🔗Share信封 An enclosing structure or cover, such as a membrane; a space between two membranes"The virus has protein envelopes that help it enter cells. "这种病毒具有蛋白质外膜，帮助它进入细胞。anatomybiologymedicinestructureChat with AIVocabulary GamePractice Reading
noun🔗Share性能范围，技术指标。 The set of limitations within which a technological system can perform safely and effectively."The safety envelopes for the new amusement park ride clearly state the maximum height and weight allowed for each passenger. "新型游乐设施的安全性能范围明确规定了每位乘客允许的最大身高和体重。technologysystemtechnicalChat with AIVocabulary GamePractice Reading
noun🔗Share彗发，彗头大气。 The nebulous covering of the head or nucleus of a comet; a coma."Through the telescope, the comet's envelopes, glowing faintly, expanded as it approached the sun. "通过望远镜，彗星的彗发发出微弱的光芒，随着它接近太阳而不断扩大。astronomyspaceChat with AIVocabulary GamePractice Reading
noun🔗Share胸墙，护墙。 An earthwork in the form of a single parapet or a small rampart, sometimes raised in the ditch and sometimes beyond it."Because the attack came from multiple directions, the defenders built envelopes around the outer fort, creating additional layers of protection. "由于攻击来自四面八方，守军在外围堡垒周围修筑了多重胸墙，增加了额外的防御层级。militaryarchitectureChat with AIVocabulary GamePractice Reading
