What are Properties in Object-Oriented Programming?

In object-oriented programming, a property is a characteristic or attribute of an object that can be accessed and modified. It is a way to encapsulate data within an object and provide a controlled interface for accessing and modifying that data.

For example, a `Car` object might have properties like `color`, `make`, and `model`, which describe the car's appearance and specifications. The `Car` object would have methods like `drive()` and `park()`, which would manipulate the car's state (e.g., start the engine, put the car in gear).

Properties are typically defined using getters and setters, which are methods that allow you to access and modify the property's value. For example:
```
class Car {
private $color;

public function __construct($color) {
$this->color = $color;
}

public function getColor() {
return $this->color;
}

public function setColor($newColor) {
$this->color = $newColor;
}

public function drive() {
// code to start the engine and put the car in gear
}

public function park() {
// code to stop the engine and put the car in park
}
}
```
In this example, the `Car` object has a property called `color`, which is private (i.e., it can only be accessed and modified by the object itself). The `getColor()` method allows you to retrieve the current value of the `color` property, while the `setColor()` method allows you to set a new value for the `color` property.

Properties are a fundamental concept in object-oriented programming, and they provide a way to encapsulate data within an object and control access to that data.