Among the Germanic tribes living along the Rhine around the time of the fall of the Roman Empire, the name Adalheidis was a popular one, especially for the daughter or wife of a chief. The name meant "of a noble family", and contained the elements adal "noble, nobility" and heid "kind, sort, type, kin, family, rank" (related to the English suffix -hood, as in knighthood). Adalheidis descended eventually into French and then English as Adelaide (Heidi is a shortened form of that name). It was the name of St. Adelaide, the Queen of Otto the Great of the Holy Roman Empire, and gained a lot of popularity from her. But when it encountered Old French in the 600 or 700's AD, it was shortened to Alice; and from there it became popular in English (and in Irish as Ailís.)
In medieval times, the French, who were particularly fond of this name, gave it a diminutive suffix -on, creating Alison, meaning literally "little Alice". Alison then became a popular name in its own right, and was found throughout England, France and Scotland until the 15th century. At that point — for whatever reason — it fell from favor in England and France. But it remained strong in Scotland, perhaps because the Scots already had a family name Allison or Ellison (of unknown origin, but probably from Yorkshire, and thus Germanic). Then, in the 19th century, Alison's popularity began to spread out from Scotland again, and was picked up across the French and English-speaking world.
Spiritually, the name Alison begins with the same balanced, expansive energy as Alp, alpha, altitude, and alto. The expansion gives way to a brief period of stasis, and then is released in light, increase, and finally grounding.