Easton's Bible Dictionary (1897)
(Gr. parakletos), one who pleads another’s cause, who helps another by defending or comforting him. ). It is applied to Christ in 1 John 2:1, where the same Greek word is rendered “Advocate,” the rendering which it should have in all the places where it occurs. Tertullus “the orator” (Acts 24:1) was a Roman advocate whom the Jews employed to accuse Paul before Felix.
Smith's Bible Dictionary (1863)
or Paraclete, one that pleads the cause of another. e. (see margin of Revised Version) Advocate, Helper, Intercessor. This use of the word is derived from the fact that the Jews, being largely ignorant of the Roman law and the Roman language, had to employ Roman advocates in their trials before Roman courts.
Hastings' Dictionary of the Bible (1898) & Schaff's Bible Dictionary
AD'VOCATE, or PAR'ACLETE. 1 John 2:1. One who pleads another's cause, a counsellor, an intercessor. It is the term used by Christ to describe the office of the Holy Spirit, John 14:16; John 15:26; John 16:7, but translated in A. V. " It is also applied to Christ as our intercessor. 1 John 2:1. The forensic office of advocate was unknown among the Jews before their subjection to the Romans; then they were obliged to conduct their trials before the Roman magistrates after the Roman manner.
Their ignorance of their conquerors' law compelled them to employ advocates or lawyers speaking Greek and Latin. Such an advocate was Tertullus, whom the Jews hired to accuse Paul before Felix. Acts 24:1. See Trial.