Here's another of Blake's Words (with 254 occurrences) that (at the least) conveys various meanings throughout his works .
Three of them are in The Marriage of Heaven and Hell. In this work Blake primarily used irony throughout: the most (truly) godly characters are given diabolic names:
Plate Five reads
"....The history of this is written in Paradise Lost. & the Governor or Reason is call'd Messiah.
And the original Archangel or possessor of the command of the heavenly host, is calld the Devil or Satan and his children are call'd Sin & Death
But in the Book of Job Miltons Messiah is call'd Satan. For this history has been adopted by both parties"
In The Four Zoas we begin to see another of the special uses Blake made of the word, Satan:
"And first he found the Limit of Opacity & namd it Satan
In Albions bosom for in every human bosom these limits stand
And next he found the Limit of Contraction & namd it Adam" (FZ4-56.19-21; E338)
Which is to say that the higher nature was completely opaque to Satan, just as Shakespeare or Latin or Greek is opaque to most of us.
And now here's a more proper use of Satan, closer to the general common useage, describing the climax of Urizen's futile attempt to order the universe in accordance with his Book of Brass:
"But Urizen his mighty rage let loose in the mid deep
Sparkles of Dire affliction issud round his frozen limbs
Horrible hooks & nets he formd twisting the cords of iron
And brass & molten metals cast in hollow globes & bor'd
Tubes in petrific steel & rammd combustiles & wheels
And chains & pullies fabricated all round the heavens of Los
Communing with the Serpent of Orc in dark dissimulation
And with the Synagogue of Satan in dark Sanhedrim
To undermine the World of Los & tear bright Enitharmon
To the four winds hopeless of future."
For Blake the Synagogue of Satan was a pet symbol; he used it 9 times, and a good example is found in plate 52 of Jerusalem:
"Man must & will have Some Religion; if he has not the Religion of Jesus, he will have the Religion of Satan, & will erect the Synagogue of Satan. calling the Prince of this World, God; and destroying all who do not worship Satan under the Name of God. Will any one say: Where are those who worship Satan under the Name of God! Where are they? Listen! Every Religion that Preaches Vengeance for Sins the Religion of the Enemy & Avenger; and not the Forgiver of Sin, and their God is Satan, Named by the Divine Name Your Religion O Deists: Deism, is the Worship of the God of this World by the means of what you call Natural Religion and Natural Philosophy, and of Natural Morality or Self-Righteousness, the Selfish Virtues of the Natural Heart. This was the Religion of the Pharisees who murderd Jesus. Deism is the same & ends in the same."