A trend is the general direction of a data point over a period of time. A pattern is a series of data that repeats in a recognizable way. Simple examples could be the trend of average body weight first by position, shown in the following screenshot:
Trend of average body weight first by position
And then, the trend of average body weight for the WR position:
Trend of average body weight for the WR position
You can use Watson Analytics to easily create some simple trend visualizations such as the ones just shown. Again, you can just ask Watson by typing a question starting with what is the trend: