We want to talk and write about things.
We use the word object with its usual sense in the English language. Objects that we can touch we call tangible. Otherwise, we say that the object is intangible. Intangible objects are also called abstract.
A pebble is a tangible object. It is an object, surely, and we can hold and touch it, of course.
The color of the pebble is intangible. We can call it an object also, even though we can not hold it or touch it. Because we can not touch it, the color is intangible.
These sheets discuss other intangible objects and little else besides.