(physics) interferometer

physics (as an area of study)

to use / to employ / to make use of, to apply / to spend

interference

to interfere

he / distal demonstrative, something far off removed from both speaker and listener: that / boyfriend

distal demonstrative, something far off removed from both speaker and listener: that, yon / particularly, male personal third person pronoun: he / by extension from he: boyfriend

he; boyfriend

plan, total

physics, the physical aspects of a phenomenon or a system