na-adjective
adjustable; modulatable
Describes something whose settings, level, or parameters can be changed. Common in technical and everyday contexts.
この椅子は高さが調整可能です。
The height of this chair is adjustable.
音量は調整可能なつまみで変えられます。
The volume can be changed with an adjustable knob.
Similar meaning, but 調節可能 often implies finer or more precise regulation, while 調整可能 is broader for general adjustment.
Compound of 調整 (adjustment) + 可能 (possible). The derivation is transparent from its components.