From BiblePortal Wikipedia

Charles Buck Theological Dictionary [1]

The followers of Macedonius, bishop of Constantinople, who, through the influence of the Eunomians, was deposed by the council of Constantinople in 360, and sent into exile. He considered the Holy Ghost as a divine energy diffused throughout the universe, and not as a person distinct from the Father and the Son. The sect of the Macedonians was crushed before it had arrived at its full maturity, by the council assembled by Theodosius in 381, at Constantinople.

See Semi-Arians

Holman Bible Dictionary [2]

 Acts 19:29 Acts 27:2 2 Corinthians 9:2Macedonia

The Nuttall Encyclopedia [3]

A sect in the early Church who taught that the Holy Ghost was inferior to the Father and the Son, so called from Macedonius, bishop of Constantinople, their leader.