This is the 665th most frequent Chinese word.
同事
Colleague.
In this sentence, '同事' is used to refer to coworkers in general within an organization.
我们公司有五十位同事。
Our company has fifty colleagues.
Here, '同事' refers to specific coworkers with whom a social interaction took place.
昨天和几个同事一起吃饭了。
Yesterday, I had a meal with several colleagues.
In this sentence, '同事' is used as a singular noun to refer to a newly joined coworker.