Concise Bible Dictionary:

The divinely appointed system of Jewish ordinances which formed the enclosure into which the Lord entered by the door, in order to find His own sheep and lead them out. Gentile believers were added to them, and they became one flock (not “one fold”) with one Shepherd, the Lord Himself (John 10:1, 3, 161Verily, verily, I say unto you, He that entereth not by the door into the sheepfold, but climbeth up some other way, the same is a thief and a robber. (John 10:1)
3To him the porter openeth; and the sheep hear his voice: and he calleth his own sheep by name, and leadeth them out. (John 10:3)
16And other sheep I have, which are not of this fold: them also I must bring, and they shall hear my voice; and there shall be one fold, and one shepherd. (John 10:16)
). There is no longer a fold on earth for those that are Christ's. They are formed into the church, namely, the one flock.
Sheepfold—Taken at Beit Sahur, December 4, 1937