"On casual Fridays, we can kick back a little and take it easy." “每周五便装日，我们可以稍微放松一下”。

Casual, "casual," is the same as informal. 随便的（casual），与“非正式的”的意思相同。

In many companies in the United States, they have casual Friday, and that's a day where you do not have to wear as nice of clothing. 美国很多公司都有周五便装日，那天你不必穿好看的衣服。

Maybe you'll wear a t-shirt and not a suit jacket, or you don't have to wear a tie, and it's also a day where people feel a little more relaxed. 也许你会穿T恤衫和非西装的外套，或者你不必打领带，那也是人们感到较为放松的一天。

Usually it has to do with what you can wear to work. 周五便装日常常与你能穿什么去工作有关。

Well, in the story I say that "On casual Fridays, we can kick back a little and take it easy." 好了，故事中我说“每周五便装日，我们可以稍微放松一下”

To kick back, "kick back," (two words) means to relax. “kick back,”（两个字）是“放松”的意思。

It's an informal expression that means that you are relaxing, and take it easy also means relax. 它是你说你在放松时的非正式表达，“take it easy”也是“放松”的意思。

Kick back is a little more informal; it's something that you might do, for example, with your friends. “Kick back”更为不正式；比如，它可能是你和你朋友在一起时会做的事。

And, if you drink alcohol, you might have some alcohol and relax; that's to kick back. 并且，如果你喝酒的话，你可能会喝点酒来放松；这就是“kick back”的意思。