Eduth means testimony, witness, or decree. It appears about 60 times. It primarily refers to the tablets of the law (the 'testimony') kept in the Ark of the Testimony, and by extension God's revealed will and covenant stipulations.
The 'testimony' in the Ark was the physical embodiment of God's covenant with Israel. The tabernacle was called the 'Tabernacle of the Testimony.' God's testimonies in the Psalms (119) are His reliable, trustworthy declarations that guide the faithful.