Holy Ghost - Holy Spirit
Moses gives us a definition of the Holy Ghost or Holy Spirit.
Therefore it is given to abide in you; the record of heaven; the Comforter; the peaceable things of immortal glory; the truth of all things; that which quickeneth all things, which maketh alive all things; that which knoweth all things, and hath all power according to wisdom, mercy, truth, justice, and judgment. (Moses 6:61)
When I read "it is given to abide in you . . . the Comforter" of course I know that it is talking about the Holy Ghost. But then I realize that I need to accept all of the verse and it's implication about how I need to understand the Holy Ghost.
And he being the Only Begotten of the Father, full of grace and truth, and having overcome, received a fullness of the glory of the Father - possessing the same mind with the Father; which Mind is the Holy Spirit, that bears record of the Father and the Son; and these three are one, or in other words, these three constitute the great, matchless, governing, and supreme power over all things; by whom all things were created and made, that were created and made: and these three constitute the Godhead and are one: the Father and the Son possessing the same mind, the same wisdom, glory, power, and fullness; (Lecture 5:2)
Here is a more complete discussion about the Holy Ghost.