Meaning of "笑" in the Chinese dictionary

Smile is a psychological state of expression. Under normal circumstances laugh more used to express pleasure and happiness, by the facial muscles as a way of expression. It is mostly due to human senses (especially the eyes, ears) contact with the outside world of things or language, into the information into the cerebral cortex, and then through the brain on the face or even the body of the muscles issued by the command of the movement. Laughter sometimes not only make muscle movement, vocal cords will also be vibrating, resulting in laughter. At present, psychologists believe that laughter is a kind of ancient way of communication between mankind, but before people think that laughter is only a sense of humor. Laughter is often used as a way of flirting to others. Many animals will laugh, some mammals exposed teeth is the form of provocation and deterrence. There is also a chemical substance nitrous oxide is commonly known as "laughing gas", this is because people inhalation of the gas will be involuntary laugh, but this material harmful to humans. ... 笑（smile）是一种心理状态的表达。一般情况下笑更多的用来表达高兴和快乐，由脸部肌肉动作为表现方式。它大都是由于人体感官（尤指眼睛、耳朵）接触外界的事物或语言，转变为信息传入大脑皮层，而后通过大脑对脸部甚至全身的肌肉发出运动的命令而产生的。笑有时不仅会使肌肉发生运动，声带也会随之振動，由此产生笑声。目前心理学家们认为笑是人类之间交流的古老的方式的一种，但之前人们更多地认为笑仅是幽默感的表现。笑也常被当作对他人调情的一种方式。 很多动物都会笑，一些哺乳动物露出牙齿则是挑衅以及威慑的表现形式。 亦有一种化学物质一氧化二氮被俗称为“笑气”，这是因为人在吸入该气体后会不自主地发笑，但这种物质对人体有害。...