Interestingly, though both this word and “adjust” are derived from the French this one retained a spelling reminiscent of French and a specialised usage.
adjutage, ajutage
lit. An adjustment, adaptation, or addition: hence in Hydraulics, A tube adapted or adjusted to a pipe or aperture through which water passes, so as to determine the character of the jet; the efflux-tube or mouthpiece of an artificial fountain.
Neh 