George Reynolds and Janne M. Sjodahl discuss and define Kolob; calls it a star.
George Reynolds and Janne M. Sjodahl, Commentary on the Pearl of Great Price (Salt Lake City: Deseret Book, 1965), 309–310
Concerning the greatest of these celestial orbs, the Book of Abraham teaches us, that,
Kolob is the greatest of all the stars which Abraham saw.
It is so because it is nearest to the residence of God.
It is nigh unto the throne of God.
It governs all the planets which belong to the same order as the earth.
It is after the reckoning of the Lord's time.
It is after the manner of the Lord according to its times and seasons and the revolutions thereof.
One revolution is one day with the Lord.
One day, in Kolob, is equal to a thousand years according to the measurement of time of this earth.
Kolob signifies first creation.
It is the first in government, and last pertaining to the measurement of time. The measurement according to Celestial time signifies one day to a cubit.
. . .
First, the Lord drew Abraham's attention to the sun, which He said is SHINEHAH; and KOLOB, which is star; OLEA, the moon, and KOKAUBEAM, which signifies stars, or "all the great lights which were in the firmament of heaven."