Introduction:
When measuring an object, it is important to understand the different dimensions that can be measured. Length, height, and width are three common dimensions used to describe the size and shape of an object. In this case, we are specifically considering the measurement direction when measuring upwards.

Explanation:
- Length: Length is a measurement of how long an object is from one end to the other. It is typically measured in a horizontal direction, such as the length of a table or a piece of string.
- Height: Height is a measurement of how tall an object is from its base to its top. It is typically measured in a vertical direction, such as the height of a person or a tree.
- Width: Width is a measurement of how wide an object is from one side to the other. It is typically measured in a horizontal direction, such as the width of a door or a book.

When the question states "Length measured upwards," it is specifically referring to measuring the length of an object in an upward direction. This means that the measurement is taken from the bottom of the object and extends vertically to the top. This type of measurement is commonly used when determining the height of an object or when measuring the length of something that extends vertically, such as a pole or a tree trunk.

Conclusion:
Therefore, when measuring upwards, the correct term to use is "height." Height is the measurement that describes the vertical extent of an object, making it the appropriate answer in this case.