One thing I've noticed in recent years is a handful of terms being used to describe interaction with a button in a graphical user interface.
Historically, we've used the term “Click”, as in “the user clicks the button”. This has made sense, because the traditional method of interacting with a button on screen has been with a mouse, and the main interaction of a mouse is to press it until its own button clicks, which also emits a clicking sound. As trackpads in notebook computers have become more prevalent, this clicking metaphor has broken down slightly.
Continuing the erosion of the button-click metaphor, direct manipulation touch screen devices (like iPhones) remove any physical mechanism entirely, leaving only a slab of glass between the user and the interface. Instead of clicking a mouse, the user taps their finger directly on the device and no sound is emitted. These are often referred to as “Taps”.
So now we have two competing terms for essentially the same action: Clicking and Tapping. Unfortunately, neither of these terms is fully applicable 100 percent of the time, and both suffer from the same problem: they describe more of the mechanism of the interaction than the interaction itself. When I say I'm clicking a button with a mouse, what I'm really saying is I'm clicking a mouse which invokes the button.
Instead, I've been using the term “Press” whenever I have to discuss an interaction with a button in a user interface. Not only does “Press” apply equally well whether a mouse, trackpad, or touch screen is used, it also relates better to what I'm doing with the interface. Pressing a button is so much more direct than clicking a mouse, which invokes the button.
The language we use to describe our interfaces can be subtle, but it's important to be precise. It can mean the difference between an indirect interaction with hardware, to an interaction with fewer mental barriers.