1.safety的基本意思是“安全,平安”,指远离危险的威胁而处于不受伤害的状态。引申可指“平安地带”。
2.safety多用作不可数名词,常用于in safety或with safety短语中。

there's safety in numbers
人多势众 being in a group makes one feel more confident
We decided to go to see the boss together, there's safety in numbers.我们决定一起去找老板,人多壮胆。
Let's try to stay together as a group; there's safety in numbers.让我们大家抱成团,人多势众嘛。

A bank assures safety for your money.银行保证你的存款安全。
There are fears for the safety of the climbers.人们担心那些登山者遇到不测。
We're keeping you here for your own safety.我们让你呆在这里是为了你自身的安全。
It's very important to teach children about road safety.把交通安全常识教给孩子们是非常重要的。
While the family were away from home, they placed all their valuables in the bank for safety.全家外出时,为了安全起见,他们把所有贵重物品交给银行保管。
You can cross the road in safety when the policeman holds up his hand to stop the cars.当警察举手让车辆暂停时,你就可以安全横过马路。
The management took all reasonable safety precautions.管理层采取了一切合理的安全措施。
Safety checks are carried out on all industrial machinery.对所有工业机械均实行安检。
We reached the safety of the river bank.我们到了河岸的安全地带。
They were busy helping survivors to safety.他们忙着帮助幸存者转移到安全地带。
At last they pulled her to safety.他们终于把她拖到了安全的地方。

for safety, in safety, with safety
这三个短语都可表示“安全地”。其侧重点不同:for safety强调目的, in safety强调动作进行时主语的状态, with safety则强调动作进行的方式。试比较：
We did it for safety.
我们为安全起见做那事。
They crossed the road in safety.
他们安全穿越马路。
Can you do it with safety?
你能安全做到吗?
safety, security
这两个词的共同意思是“安全”。其区别是:safety有“事到临头,消极逃避以免受害”的意味; 而security则有“积极防范以保证不受害”的意味。例如:
The Smiths are living in peace and security.史密斯一家过着平静安稳的生活。

别担心,他很安全。
［误］  Don't worry about him. He is in the safety.
［正］  Don't worry about him. He is in safety.
［析］  be in safety是固定用法,表示“处于安全状态或位置”, safety前不加冠词。