Definition of Apparatus the tools, equipment, and machinery you use for particular purposes Examples of Apparatus in a sentence The firefighter donned a breathing apparatus before entering the blaze, to search for people trapped in the inferno. The president’s security apparatus fanned out so that they could keep watch on all angles of the event.

Here are some examples of how to use “apparatus” in a sentence: The fire department’s apparatus includes a ladder truck, a pumper, and an ambulance. The chemistry lab has a sophisticated apparatus for analyzing chemical compounds. The gym has a variety of exercise apparatus for strength training.

Sentence Examples The outer doors are missing, the inner doors jammed, and the whole apparatus knocked out of alignment. The apparatus is advantageously used in an interferometer to form a device that modulates the amplitude of the optical signal.