You are going with the technical meanings and terms used because technically, even an investor trades when they are either buying or selling assets of their choice, but logically, an investor is different than a trader because when we say someone is an investor, we mean they intend to buy and hold an asset as an investment so that they can get capital gains when its price grows over time, whereas a trader is someone who frequently buys and sells assets to get profits on a short-term basis.

You can even think of it from other businesses' perspectives. Imagine, if we are talking about a company of watches. Someone who buys and sells watches every day or week and is always in the process of doing that is called a trader. However, if someone buys specific watches, and keeps them with himself so that he can sell them when their price goes up, he is investing in watches and isn't trading them in the logical sense.