from The American Heritage® Dictionary of the English Language, 4th Edition
- prep. To.
- prep. Until: a fast unto death.
- prep. By: a place unto itself, quite unlike its surroundings.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- conj. Up to the time or degree that; until; till.
- prep. Up to, indicating a motion towards a thing and then stopping at it.
from the GNU version of the Collaborative International Dictionary of English
- prep. To; -- now used only in antiquated, formal, or scriptural style. See To.
- prep. Until; till.
- conj. Until; till.
from The Century Dictionary and Cyclopedia
- To: now somewhat antiquated, but much used in formal or elevated style.
- They also brought a full intelligence in reference unto the particulars they were sent about.
- Up to the time or degree that; until; till.
Middle English : un-, up to; see until + to, to; see to.(American Heritage® Dictionary of the English Language, Fourth Edition)
By analogy with until, substituting to for till. (Wiktionary)