"I'm about to arrive" -> "I'm close to arrival but not here right now".
"This book is about..." -> "This book is roughly this short approximation, because I can't fit the entire synopsis in a sentence,..."
"About his person" -> "Close to him, possibly so close as to be carrying it"
"He is about" -> "He is somewhere around here, but not in this exact spot"
"He is out and about" -> "He is out somewhere in this area"
"Gone walkabout" -> "Traveling with no specific destination"
"Roundabout" -> "Traffic control method that encourages vehicles to take a more circuitous passage, rather than directly crossing an intersection"
The context of the word changes the interpretation, but the essential function of "about" is the same in each case.
"I'm about to arrive" -> "I'm close to arrival but not here right now".
"This book is about..." -> "This book is roughly this short approximation, because I can't fit the entire synopsis in a sentence,..."
"About his person" -> "Close to him, possibly so close as to be carrying it"
"He is about" -> "He is somewhere around here, but not in this exact spot"
"He is out and about" -> "He is out somewhere in this area"
"Gone walkabout" -> "Traveling with no specific destination"
"Roundabout" -> "Traffic control method that encourages vehicles to take a more circuitous passage, rather than directly crossing an intersection"
The context of the word changes the interpretation, but the essential function of "about" is the same in each case.