On-calliday is the special, and personal, time of year that you take time off from your work duties to spend with families, aka holiday, but are required by your company to be accessible (as by mobile phone, pda or laptop) to address urgent issues. That's why it is called on-call holiday (on-calliday). 待命假日（on-calliday）指每年当中放下工作、与家人共同度过的一段私人时光，也就是我们所说的“假日”；但是，公司会要求你在假日期间保持通讯畅通（比如手机开机、掌上电脑或手提电脑随时联网等），以保证有紧急事务时能够随时找到你。所以，这样的假日就叫做“待命假日（on-call holiday）”，也就是其英文表达on-calliday的由来。 For example:Have a safe on-calliday and a happy new year, don't forget to login while you enjoy your eggnog.祝你待命假日相安无事，同祝新年快乐。品尝蛋酒的时候别忘了登录网络保持在线啊。