I gave you data by showing links where other companies like Blackberry, Lenovo, Microsoft, and Asus use the word "trackpad" themselves for their own devices. Lenovo even cutely capitalizes the P to fit their ThinkPad branding. You could also google around and see random people on reddit and elsewhere talking about the "trackpads" on their dells, hps, vaios, matebooks, and so on.

I'm not saying that "touchpad" isn't more common, but the evidence _clearly_ shows that "trackpad" isn't exclusive to Apple devices.