Augmentation is a related term of adjunct.
In music|lang=en terms the difference between augmentation and adjunct
is that
augmentation is (music) a compositional technique where the composer lengthens the melody by multiplying the length of each note by the same number while
adjunct is (music) a key or scale closely related to another as principal; a relative or attendant key.
As nouns the difference between augmentation and adjunct
is that
augmentation is the act or process of augmenting while
adjunct is an appendage; something attached to something else in a subordinate capacity.
As an adjective adjunct is
connected in a subordinate function.