The device that must always be zeroed out before beginning to use it for measurement is a scale.

Here's why:

* Zeroing ensures accuracy: Scales are designed to measure the difference between the weight of an object and the weight of the scale itself. If the scale isn't zeroed, it's measuring the weight of the object plus the weight of the scale, leading to inaccurate readings.

* Types of scales: This applies to various types of scales, including:

* Bathroom scales

* Kitchen scales

* Laboratory scales

* Industrial scales

By zeroing the scale, you ensure that the reading reflects only the weight of the object being measured.